Absorbent articles containing a multifunctional gel

ABSTRACT

Improved skin-adhesive compositions for bonding a substrate, such as an absorbent article, to skin are disclosed. More particularly, the skin-adhesive composition has an improved, yet gentle, adhesion to the skin of a user, while maintaining strong, effective bonding to various inanimate, non-skin substrates. In one embodiment, the skin-adhesive composition can provide one or more skin benefit agents to the user. The skin-adhesive composition may be applied to an absorbent article, such as a panty-liner, sanitary napkin, or an incontinence article, for directly adhering the article to the skin of a user.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a divisional application of U.S. application Ser.No. 12/364,365, filed Feb. 2, 2009, which is hereby incorporated byreference in its entirety.

BACKGROUND OF THE DISCLOSURE

The present disclosure relates generally to absorbent articles forabsorbing and holding bodily fluids and, more particularly, to absorbentarticles that contain gels that exhibit adhesive and/or absorbentproperties. Furthermore, it has been found that gels that possess bothadhesive and absorbent qualities may be incorporated into absorbentarticles. In one embodiment, the present disclosure relates to anabsorbent article, such as a panty-liner, sanitary napkin, or anincontinence article, having the skin-adhesive and absorbent gelcomposition applied thereon for directly adhering the article to theskin of a user/wearer and for absorbing bodily fluids.

Absorbent personal care articles intended to absorb discharged bodilyfluids are well known in the art. Such absorbent articles generallycomprise a fibrous mass or other absorbent core which can absorb andhold body fluids. Similarly, it is well known that feminine carearticles have been employed to absorb and hold liquids, such as urineand/or menses. Conventionally, absorbent articles include a fluidimpermeable back sheet, a fluid permeable top sheet and an absorbentcore positioned between the back sheet and the top sheet. Priorabsorbent articles have also included various other features to improvefluid handling, such as intake layers, distribution layers, retentionlayers and the like. In these absorbent personal care articles, the topsheet is the body-facing side of the absorbent article and the backsheet is the garment-facing side of the absorbent article.

Generally, the absorbent articles are held in place during use by usingthe wearer's waist and elastic materials in the waist portion of theabsorbent product in place during use, in the case of pant-likegarments, such as diapers and training pants, or by attaching theabsorbent article to the underwear or undergarment of a wearer, in thecase of pads or panty-liners. Current methods of attaching the absorbentarticle to the underwear or undergarment of a wearer include utilizingan adhesive placed on the garment-facing side of the back sheet and,optionally or alternatively, utilizing flaps (wings) that extend fromthe longitudinal sides of the absorbent article which wrap around thecrotch portion of the underwear or undergarment of the wearer.

It has also been suggested to use an adhesive to adhere the absorbentarticle to the skin of the wearer as described in U.S. application Ser.No. 12/267,806, the contents of which are incorporated herein for allrelevant and consistent purposes.

A need exists for absorbent articles that include materials that aremultifunctional and, specifically, materials that provide bothabsorption and adhesion to the wearer. Such absorbent articles would becharacterized by decreased complexity. Further, an absorbent materialthat also functions as an adhesive would move as the body moves allowingfor superior leak protection during periods or increased activity ormovement by the wearer. Such a material would also reduce gappingbetween the material and the body of the wearer thus increasing fluidintercept and reducing the potential for fluid leak.

BRIEF DESCRIPTION OF THE DISCLOSURE

It has been found that skin-adhesive and absorbent gel compositions canbe produced and included in absorbent articles for improved bonding ofthe substrates and articles directly to the skin of a user.Particularly, utilization of the skin-adhesive and absorbent gelcompositions in absorbent articles reduces gapping between the materialand the body of the wearer thus increasing fluid intercept and reducingthe potential for fluid leak. Generally, the skin-adhesive and absorbentgel compositions of the present disclosure include hydrogels and/oraerogels that are skin-adhesive and absorbent. It has been found thatthe skin-adhesive and absorbent gel compositions allow the adhesive tomaintain its bonding strength with the substrate and have improvedbonding strength with the skin, yet remain gentle on the skin's surface.In one embodiment, the skin-adhesive and absorbent gel compositionfurther includes at least one skin benefit agent for providing improvedskin health to the user.

The skin-adhesive and absorbent gel composition may be applied tovarious substrates. Particularly, in one embodiment, the skin-adhesiveand absorbent gel composition is applied to the body-facing side of afluid-impermeable substrate of an absorbent article. Examples ofabsorbent articles include, for example, a panty-liner, sanitary napkinor incontinent article.

In one aspect of the present disclosure, an absorbent article comprisesa fluid impermeable substrate having a body-facing surface and agarment-facing surface. The body-facing surface has a skin-adhesive andabsorbent gel composition thereon for adhering the substrate directly toa wearer and for absorbing bodily fluids.

In another aspect of the present disclosure, an absorbent articlecomprises a fluid impermeable substrate, an absorbent core and aperforated liner. The fluid impermeable substrate has a body-facingsurface and a garment-facing surface. The absorbent core is interposedbetween the substrate and perforated liner and comprises an absorbentgel composition.

Other objects and features will be in part apparent and in part pointedout hereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a top view of an embodiment of an absorbent article of thepresent disclosure;

FIG. 2 shows a bottom view of the absorbent article shown in FIG. 1;

FIG. 3 shows a top view of a second embodiment of an absorbent articleof the present disclosure;

FIG. 4 shows a cross-section of a third embodiment of an absorbentarticle of the present disclosure; and

FIG. 5 shows a cross-section of a fourth embodiment of an absorbentarticle of the present disclosure.

Corresponding reference characters indicate corresponding partsthroughout the drawings.

Definitions

It should be noted that, when employed in the present disclosure, theterms “comprises”, “comprising” and other derivatives from the root term“comprise” are intended to be open-ended terms that specify the presenceor any stated features, elements, integers, steps, or components, andare not intended to preclude the presence or addition of one or moreother features, elements, integers, steps, components, or groupsthereof.

When introducing elements of the present disclosure or the preferredembodiment(s) thereof, the articles “a”, “an”, “the” and “said” areintended to mean that there are one or more of the elements. The terms“comprising”, “including” and “having” are intended to be inclusive andmean that there may be additional elements other than the listedelements.

It should be understood that the term “absorbent product” or “absorbentarticle”, as used herein, refers to any article used to control bodilyfluids that are configured to absorb and retain bodily exudates,including urine, blood, menses, and other bodily discharges, such assweat and vaginal secretions resulting from sexual activity and thelike. In addition, the term is intended to include odor absorbingarticles. Absorbent articles include diapers, tampons, incontinencearticles, and the like.

As used herein, the term “polymer” generally includes, but is notlimited to, homopolymers, copolymers, such as, block, graft, random andalternating copolymers, terpolymers, etc., and blends and modificationsthereof. Furthermore, unless otherwise specifically limited, the term“polymer” shall include all possible geometrical configurations of thematerial. These configurations include, but are not limited to,isotactic, syndiotactic and random symmetries.

As used herein, “adhesion modifier” refers to an agent that allows theadhesive of the gel composition to maintain its bonding strength withthe substrate and improve its bonding strength with skin, yet remaingentle on the skin's surface. Furthermore, the adhesion modifier behavesas a delivery vehicle or carrier to aid in the delivering of one or moreskin benefit agents to the skin of the user. Typically, the adhesionmodifier has a polymer-like or matrix network structure that may havenumerous micropores or channels, which can hold the skin benefit agentas described below. Suitable adhesive modifiers may include, forexample, POLY-PORES, POLYTRAPS, and the like. Particularly suitableexamples, described more fully below, include POLYTRAP 7603, which is anallyl methacrylate/glycol dimethacrylate crosspolymer; POLYTRAP 6603,which is a lauryl methacrylate/glycol dimethacrylate crosspolymer;POLY-PORE E200 and POLY-PORE L200, both of which are allyl methacrylatecrosspolymers.

As used herein, “body-facing surface” means that surface of theabsorbent article or any structure that is part of the absorbent article(for example, liner, absorbent core, gel composition) which is intendedto be disposed toward or placed adjacent to the body or skin of thewearer during ordinary use. The “garment-facing surface” is on theopposite side of the absorbent article from the body-facing surface. Thegarment-facing surface is an outward surface of the fluid impermeablesubstrate and is intended to be disposed to face away from the wearer'sbody during ordinary use. The garment-facing surface is generallyarranged to face toward or placed adjacent to the wearer's undergarmentswhen the absorbent article is worn.

As used herein, the term “connected” is intended to mean directlyconnected and indirectly connected. By directly connected, it isintended that the connected elements are in contact with one another oraffixed or adhered to one another. By indirectly connected, it isintended that one or more intervening or intermediate elements arebetween the two elements which are secured or “connected” together. Theintervening elements may be affixed or adhered.

As used herein, the term “attached” is intended to mean directlyattached and indirectly attached. By directly attached, it is intendedthat the attached elements are in contact with one another or affixed oradhered to one another. By indirectly attached, it is intended that oneor more intervening or intermediate elements are between the twoelements which are secured or “attached” together. The interveningelements may be affixed or adhered.

As used herein, the term “fluid impermeable substrate” is intended tomean any substrate known in the absorbent articles, health careproducts, and/or personal care product art that is generally capable ofmaintaining a dry garment-facing surface upon exposing the body-facingsurface to water or other bodily fluids. Health care products includeproducts such as masks, surgical gowns, gloves, and the like.

As used herein, the term “hydrogel” or “hydrogel composition” refers toa polymeric material that is capable of absorbing more than about 20%its weight in water while maintaining a distinct three-dimensionalstructure. Additionally, the term “hydrogel monomer” may refer to thepolymerizing formulation or hydrogel precursor composition (includingthe hydrogel monomer) which is converted to a hydrogel whenpolymerization is triggered via conventional processes such as UVradiation (or UV curing), gamma rays, electron-beam, heat, chemicalinitiation, etc., as discussed elsewhere herein.

As used herein, the term “aerogel” refers to a low density material inwhich the liquid has been replaced by a gas. Aerogels include allaerogel forms including, for example, inorganic aerogels, organicaerogels (particularly carbon aerogels), and xerogels (gels formed whenhydrogels are air dried as opposed to supercritically dried).

As used herein, the term “fibrous web” includes any web having astructure of individual threads (e.g., fibers or filaments), includingwoven webs, nonwoven webs, scrim, knitted webs, etc.

As used herein, the term “nonwoven web” refers to a web having astructure of individual threads (e.g., fibers or filaments) that arerandomly interlaid, not in an identifiable manner as in a knittedfabric. Nonwoven webs include, for example, meltblown webs, spunbondwebs, carded webs, wet-laid webs, airlaid webs, coform webs,hydraulically entangled webs, etc. The basis weight of the nonwoven webmay generally vary, but is typically from about 5 g/m² to 200 g/m², insome embodiments from about 10 g/m² to about 150 g/m², and in someembodiments, from about 15 g/m² to about 100 g/m².

As used herein, the term “meltblown web” generally refers to a nonwovenweb that is formed by a process in which a molten thermoplastic materialis extruded through a plurality of fine, usually circular, diecapillaries as molten fibers into converging high velocity gas (e.g.air) streams that attenuate the fibers of molten thermoplastic materialto reduce their diameter, which may be to microfiber diameter.Thereafter, the meltblown fibers are carried by the high velocity gasstream and are deposited on a collecting surface to form a web ofrandomly dispersed meltblown fibers. Such a process is disclosed, forexample, in U.S. Pat. No. 3,849,241, which is incorporated herein forall relevant and consistent purposes. Generally speaking, meltblownfibers may be microfibers that are substantially continuous ordiscontinuous, generally smaller than 10 micrometers in diameter, andgenerally tacky when deposited onto a collecting surface.

As used herein, the term “spunbond web” generally refers to a webcontaining small diameter substantially continuous filaments. Thefilaments are formed by extruding a molten thermoplastic material from aplurality of fine, usually circular, capillaries of a spinnerette withthe diameter of the extruded filaments then being rapidly reduced as by,for example, eductive drawing and/or other well-known spunbondingmechanisms. The production of spunbond webs is described andillustrated, for example, in U.S. Pat. Nos. 4,340,563, 3,692,618,3,802,817, 3,338,992, 3,341,394, 3,502,763, 3,502,538, 3,542,615, and5,382,400, which are incorporated herein for all relevant and consistentpurposes. The filaments may, for example, have a length much greaterthan their diameter, such as a length to diameter ratio (“aspect ratio”)greater than about 15,000:1, and in some cases, greater than about50,000:1. The filaments may sometimes have diameters less than about 40micrometers, and are often between about 5 to about 20 micrometers.

As used herein “carded webs” refers to nonwoven webs formed by cardingprocesses as are known to those skilled in the art and furtherdescribed, for example, in U.S. Pat. No. 4,488,928, which isincorporated herein for all relevant and consistent purposes. Briefly,carding processes involve starting with staple fibers in a bulky battthat is combed or otherwise treated to provide a generally uniform basisweight. A carded web may then be bonded by conventional means as knownin the art such as, for example, through air bonding, ultrasonic bondingand thermal point bonding.

As used herein, an “airlaid” web is a fibrous web structure formedprimarily by a process involving deposition of loose, air-entrainedfibers onto a porous or foraminous forming surface. Generally, the webincludes cellulosic fibers such as those from fluff pulp that have beenseparated from a mat of fibers, such as by a hammermilling process, andthen entrained in a moving stream of air and deposited or collected onthe forming screen or other foraminous forming surface, usually with theassistance of a vacuum supply, in order to form a dry-laid fiber web.There may also be other fibers such as thermoplastic staple fibers orbinder fibers present, and typically following collection of the fiberson the forming surface the web is densified and/or bonded by suchmethods as thermal bonding or adhesive bonding. In addition, superabsorbent materials in particulate or fiber form may be included inairlaid webs where desired. Equipment for producing air-laid websincludes the Rando-Weber air-former machine available from PandaCorporation of New York and the Dan-Web rotary screen air-former machineavailable from Dan-Web Forming of Risskov, Denmark.

DETAILED DESCRIPTION OF THE DISCLOSURE

Referring now to FIG. 1, an absorbent article constructed generally inaccordance with the principles of the present disclosure is designatedas 100. As illustrated in FIGS. 1-2, the absorbent article 100 has alongitudinal direction 1 and a lateral direction 2. One component of theabsorbent article 100 is a substrate 114. This substrate 114 has a firstside 115, as shown in FIG. 1, and a second side 117, as shown in FIG. 2.The substrate 114 serves to provide the overall contour or silhouette ofthe absorbent article 100. In addition, the substrate 114 also providesa surface for attachment or adhesion of the absorbent article 100 to thebody of a wearer.

The first side 115 of the substrate 114 is the body-facing side of thesubstrate and the second side 117 of the substrate is the garment-facingside. The first side 115 of the substrate 114 is generally designed oradapted for contact with the wearer's skin.

The absorbent article 100 has a skin-adhesive and absorbent gelcomposition 121 attached to the first side 115 of the substrate 114. Thegel composition 121 has a first side 130 that is the body-facing side ofthe composition and a second side 132 that is the garment-facing side ofthe gel.

Generally, the substrate 114 is sized and shaped such that the firstside 115 of the substrate only contacts or adheres to the skinsurrounding and proximate to the vulva area and possibly the pubic andperinea regions of the wearer. The skin-adhesive and absorbent gelcomposition 121 is sized and shaped so that generally the first side 130of the gel composition contacts the vulva region of the wearer. Thefirst side 130 of the gel composition 121 is what holds the absorbentarticle in place on the body of a wearer.

The absorbent article 100 of the present disclosure is designed toadhere to the body of a wearer in the area of the body of the wearerwhich may need bodily fluids absorbed. In one particular use of theabsorbent article, the absorbent article is attached to the body of afemale wearer to or around the vulva region of the body. By “to oraround the vulva region”, it is meant adjacent regions of the body of afemale including the vulva, pubic region and the perinea region. Whenapplied to or around the vulva region of the female body, the absorbentarticle may be used as a panty-liner, sanitary napkin or incontinencearticle. In addition, the absorbent article may be worn as an underwearsubstitute since the absorbent article of the present disclosure doesnot need underwear to hold the absorbent article in place. As anunderwear substitute, the absorbent article provides protection to thevulva area by creating a barrier between the outer clothing and thevulva of a wearer. When worn as an underwear substitute, the absorbentarticle serves to protect the outer clothing of the wearer from bodilydischarges from the vulva region of the wearer's body. In addition, whenthe absorbent article is worn as an underwear substitute, the absorbentarticle also serves to protect the sensitive skin and body features ofthe vulva region from roughness of the outer clothing, therebypreventing or alleviating irritation to the sensitive skin and bodyfeatures of the vulva region. While described herein as a femalepersonal article such as a panty-liner or sanitary napkin, it should berecognized by one skilled in the art that the absorbent article can beany absorbent article in the personal care art, and further, the userneed not be a female.

The Substrate

The substrate 114 of the absorbent article 100 may be prepared from avariety of materials. The substrate may include a layer constructed ofany material which will function to be operatively fluid impermeable.The substrate 114 may, for example, include a polymeric film, a wovenfabric, a nonwoven fabric or the like, as well as combinations orcomposites thereof. For example, the substrate 114 may include a polymerfilm laminated to a woven or nonwoven fabric. A laminate substrate 114structure is shown in FIG. 5, having an upper layer 141 and a lowerlayer 142, wherein the upper layer 141 is the body-facing side of thesubstrate 114 and the lower layer 142 is the garment-facing side of thesubstrate. In a particular embodiment, the polymer film can be composedof polyethylene, polypropylene, polyester, silicone or the like, as wellas combinations thereof. Additionally, the polymer film may bemicro-embossed, have a printed design, have a printed message to theconsumer, and/or may be at least partially colored.

Suitably, the substrate 114 can operatively permit a sufficient passageof air and moisture vapor out of the absorbent article 100, particularlyout of an skin-adhesive and absorbent gel composition 121 while blockingthe passage of bodily fluids and odors often associated with bodilyfluids. An example of a suitable substrate material can include abreathable, microporous film, such as those described in, for example,U.S. Pat. No. 6,045,900, which is incorporated herein by reference forall relevant and consistent purposes. Other substrate materials whichare extensible may be used in the present disclosure, including, forexample foams. One example of a suitable foam is a polyurethane foamwith a negative Poissons ratio. Examples of extensible backsheetmaterials are described in U.S. Pat. No. 5,611,790, which isincorporated herein by reference for all relevant and consistentpurposes. Other materials that are inherently breathable, such aspolyurethanes, may be used to form the substrate 114.

In one particular embodiment of the present disclosure, the substrate114 may be a laminate of a woven or nonwoven fabric with a siliconepolymer. The second side 117 of the substrate will be woven or nonwovenfabric and the first side 115 of the substrate will be silicone polymer.One commercially available laminate is an OLEEVA FABRIC available fromBio Med Sciences, Inc. (Allentown, Pa.). The OLEEVA FABRIC is a siliconesheeting having adhesive properties laminated to a fabric backing. Thesilicone sheeting will form the body-facing first side 115 of thesubstrate material. Relating this particular structure to the Figures,in FIG. 5, the silicone polymer is the upper layer 141 of the substrate114 and the nonwoven or woven layer is the lower layer 142 of thesubstrate. In one embodiment, the polymer film is composed ofpolyethylene, polypropylene, polyester, silicone or the like, as well ascombinations thereof. Additionally, the polymer film may bemicro-embossed, have a printed design, have a printed message to theconsumer, and/or may be at least partially colored.

Bicomponent films or other multi-component films can also be used as thesubstrate 114 material. In addition, woven and/or nonwoven fabrics whichhave been treated to render them operatively liquid-impermeable may alsobe used as an effective substrate 114 material. Another suitablesubstrate material can include foams. Examples of foam include aclosed-cell polyolefin foam, a foam with a negative Poissons ratio andother similar foams. Other suitable polymeric materials include apolyurethane polymer material, a silicone polymer or other similarmaterials.

In another embodiment of the present disclosure, the substrate 114 maybe prepared from an interpenetrating polymer network or two or morepolymers. Generally, one of the polymers of the interpenetrating polymernetwork may be a silicone gel. Examples of interpenetrating polymernetworks are described in U.S. Pat. No. 5,759,560, which is incorporatedherein by reference for all relevant and consistent purposes.

The substrate material should be selected such that the overallproperties of the substrate allow the substrate material to move withthe skin of the wearer during normal use and normal movements by thewearer during use. By “normal movement by the wearer” it is meant anymovement that normally occurs during use of the absorbent article,including walking, running, sitting, standing, kneeling, riding abicycle, exercising, playing sports, getting into and out of anautomobile, and other similar movements made by wearers when wearing anabsorbent article. The substrate 114 should not be too rigid, such thatthe substrate detaches from the skin of the wearer during use and thesubstrate should not be so flexible that the substrate tends to twistand bunch during use. The substrate 114 should have sufficientflexibility to conform to the skin of the wearer and become similar to asecond skin of the wearer. The substrate 114 should also have theability to remain attached to the body of the wearer under moist or wetconditions.

Generally, the substrate material should have sufficient thickness toallow the substrate 114 to mold to the body of the wearer, but not toothick that the substrate 114 becomes uncomfortable for the wearer towear. In addition, the substrate 114 should not be so thin that itineffectively forms a seal with the skin of the wearer when applied tothe wearer, or becomes detached from the skin of the wearer during useand normal movement of the wearer during use or that it does notadequately conform to the shape and skin of the wearer at the point ofattachment to the wearer. Depending on the material used for thesubstrate, the typical thickness of the substrate 114 is between 0.03 mmand about 5.0 mm and, more particularly between 0.1 mm and 3.0 mm. Inone particular embodiment, the thickness of the substrate is between0.25 mm and about 3.0 mm. Again, the actual thickness used is dependentof several factors including rigidity of the material, the flexibilityof the material and the ability of the material to assume the shape ofthe skin of the wearer at the location of use.

The second side 117 of the substrate 114 may form a portion of thegarment-facing side of the absorbent article 100 when worn by a wearer.The substrate material should be selected such that the second side 117of the substrate 114 will freely move against the undergarment orclothing of a wearer. One way to achieve this result is to construct thesecond side 117 of the substrate 114 to have a fairly low coefficient offriction. This will allow the second side 117 of the substrate 114 tofreely move against the undergarment or other clothing worn by thewearer. If the second side 117 of the substrate 114, does not freelymove against the undergarment or other clothing worn by the wearer, theabsorbent article may catch on the undergarment or clothing, which mayresult in the absorbent article being prematurely and undesirablyremoved from the wearer or may cause the absorbent article to be shiftedfrom its desired placement against the body of a wearer.

In order to achieve the desired coefficient of friction on the secondside 117 of the substrate 114, the materials used to prepare thesubstrate could be selected such that the second side of the substratematerial will inherently have the desired coefficient of friction.Alternatively, the second side 117 of the substrate 114 may be treatedwith a coating composition, such a polytetrafluoroethylene-containingcoating, a silicone-containing coating or other similar coating havinglow coefficient of friction properties. Alternatively, the substrate 114could be made from a laminate of two or more materials such that thefirst side 115 of the substrate 114 is prepared from a material whichmeets the needed properties of the first side, while the materialselected for the second side 117 of the substrate meets the desiredcoefficient of friction such that the second side will move freelyagainst the undergarment or garment being worn by a wearer.

The substrate 114 of the absorbent article 100 may be flat or may have athree-dimensional shape. As is shown in FIG. 4, which is across-sectional side view of an absorbent article of one embodiment ofthe present disclosure, the substrate 114 has a three-dimensionalconcave shape. Alternatively, as is shown in cross-sectional side viewsof FIG. 5, the substrate 114 may have a generally flat shape. Byproviding the absorbent article 100 with a three-dimensional concaveshape, as is shown in FIG. 4, placement of the article may be easier forthe wearer. Generally, the three-dimensional shape could be such that itclosely matches the overall general curvature of the vulva region andoptionally the pubic and perinea regions of most women, when theabsorbent article is used as a panty-liner, sanitary napkin or afeminine incontinence article. To form the substrate 114 with athree-dimensional shape, the substrate may be molded in any manner knownto those skilled in the art, for example heat molding. The manner inwhich the three-dimensional shape is imparted to the substrate 114 isnot critical to the present disclosure.

When the substrate 114 is a generally flat shape, for example as shownin FIG. 5, meaning that the substrate does not generally have a thirddimension other than thickness, the substrate should be made to beflexible enough that the substrate can conform to the body of the wearerat the point of attachment. In addition to being flat, the overall shapeof the substrate 114 may be contoured. In one embodiment (not shown),the contour shape may be such that the narrowest point of the contour inthe crotch area of the substrate 114 nearest the vulva region. Thecontour shape is one of many possible shapes, in which the substrate 114and absorbent article may be prepared. Other shapes may be used, withoutdeparting from the scope of the present disclosure. Generally, the shapeselected should be such that the substrate 114 and absorbent article 100are comfortable for the wearer to wear, while providing leakageprotection to the wearer. It is noted that a contour shape may also beused in conjunction with a three-dimensional substrate.

The substrate may be any desired color or may be translucent. Inaddition, the substrate may have a matte finish, satin finish or asmooth finish. The particular finish color or translucency is a matterof choice for the manufacturer of the absorbent article of the presentdisclosure. However, providing a substrate 114 which is translucent mayassist the wearer in placing the absorbent article 100 prior to use,since the wearer may be able to see where the article is placed comparedto the genitalia of the wearer.

Skin-Adhesive and Absorbent Gel Compositions

The skin-adhesive and absorbent gel composition 121 is designed toabsorb body exudates, including menstrual fluid, blood, urine, and otherbodily fluids, such as sweat and vaginal discharges. The gel composition121 has a longitudinal direction 1 and a lateral direction 2 and isshown in FIGS. 1-3, and a thickness in the z-direction 3, as is shown inFIGS. 4 and 5. Generally, the gel composition 121 will be positionedadjacent to the first side 115 of the substrate 114, as can be clearlyseen in FIGS. 1-4. By “adjacent to the substrate”, it is meant that thegel composition 121 is directly in contact with the first side 115 ofthe substrate 114 or may be separated by one or two additional layers ora construction or pressure sensitive adhesive.

In addition to absorbing bodily fluids, the gel composition 121 contactsthe skin and hair, if present, in the vulva region and possibly thepubic region and/or the perinea region of the wearer's body, therebysupporting and holding the absorbent article 100 against the body of thewearer during use. The gel composition 121 should not be an irritant tohuman skin or be adhesive to the point where it causes pain to theuser/wearer when the absorbent article is removed from the skin. The gelcomposition 121 should also not leave a substantial amount of residue onthe surface of the skin of the wearer when absorbent article is removedby the wearer after use.

The gel composition 121 should form a sufficiently strong bond with thesubstrate 114 such as to prevent premature peeling or delaminating ofthe substrate or absorbent article; however, the gel composition needsto remain gently attached to the skin's surface so as to be easily andcomfortably removed and/or reapplied. Accordingly, the gel composition121 should provide a greater peel strength relating to the attachmentbetween the gel composition and the substrate than the peel strengthrelating to the attachment between the gel composition and the surfaceof a user's skin. In one embodiment, the gel composition 121 provides apeel strength of gel composition to substrate of greater than about 800grams per inch and, in other embodiments, from about 800 grams per inchto about 1500 grams per inch or from about 900 grams per inch to about1000 grams per inch.

As the gel composition 121 is applied to the skin to keep the absorbentarticle 100 in position during use, the gel composition should possess ahigh peel strength of composition to skin to hold the absorbent articlein place while remaining gentle on the skin's surface. In oneembodiment, the gel composition has a peel strength of composition toskin of from about 5 grams per inch to about 100 grams per inch and inanother embodiment from about 20 grams per inch to about 100 grams perinch. In other embodiments, the gel composition 121 has a peel strengthof gel composition to skin of less than about 50 grams per inch, lessthan about 25 grams per inch, less than about 20 grams per inch or evenless than about 5 grams per inch. In yet other embodiments, the gelcomposition has a peel strength of composition to skin of from about 75grams per inch to about 500 grams per inch or even from about 100 gramsper inch to about 200 grams per inch.

To measure peel strength of the skin-adhesive compositions, a methodsimilar to STM 5599 may be used. STM 5599 is fully described in U.S.application Ser. No. 12/267,806, which is incorporated herein for allrelevant and consistent purposes.

As shown in FIG. 1, the skin-adhesive and absorbent gel composition 121can overlie a portion of the first side 115 of the substrate 114,however, the gel composition can overlie the entire first side of thesubstrate 114 without departing from the scope of the presentdisclosure. Generally, the gel composition 121 will be present on atleast the central portion of the first side 115 of the substrate 114near the center of the absorbent article 100. The gel composition 121may also be placed in a pattern of the first side 115 of the absorbentarticle. The gel composition 121 may be applied to the first side 115 ofthe substrate 114 using any known process including inkjet printing,screen printing or extruding the skin-adhesive and absorbent compositionfrom one or more nozzles, slot coating and the like.

The skin-adhesive and absorbent gel composition 121 may be positioned onthe first side 115 of the substrate 114 in an open pattern or a closedpattern. By “open pattern” is meant that the composition has anintermittent or discontinuous pattern. For example, there may be breaksin the skin-adhesive and absorbent gel composition at certain portionsof the first side 115 of the substrate 114. In one embodiment of an“open” pattern of the skin-adhesive and gel composition, individualbeads of composition are applied in a discontinuous fashion. In a“closed pattern” the gel composition 121 is continuous. In the presentdisclosure, the closed pattern can be advantageous since theskin-adhesive and absorbent composition 121 may form a seal with theskin of the wearer which will assist in preventing leaks. Further, aclosed pattern helps increase the surface area of the gel composition121 that is available to absorb excreted bodily fluids.

In one embodiment of the present disclosure, the skin-adhesive andabsorbent gel composition 121 is placed on the entire first side 115 ofthe substrate 114 (not shown). In another alternative embodiment of thepresent disclosure and as shown in FIGS. 1-5, the gel composition 121 isplaced along the central portion of the first side 115 near the centerof the substrate 114.

In one embodiment, the weight of skin-adhesive and absorbent gelcomposition 121 of the absorbent article 100 is from about 1 g/m² toabout 450 g/m². In another embodiment, the weight of skin-adhesive andabsorbent gel composition 121 of the absorbent article is from about 50g/m² to about 150 g/m².

In some embodiments, the gel composition is capable of absorbing up toabout 20%, up to about 50%, up to about 100%, up to about 250% or evenup to about 1000% of its weight in water and, suitably, bodily fluids.

The water content of the gel composition may be determined as follows:% water content=100×(W _(w) −W _(d))/W _(w)wherein W_(w) is the weight of the wet gel composition and W_(d) is theweight of dry composition.

Generally, the gel composition 121 is applied in a manner which issymmetrical about the longitudinal axis which bisects the absorbentarticle 100 and divides the absorbent article 100 into substantiallyequal portions. This symmetrical pattern provides the wearer a balancedfeel when wearing the absorbent article 100. The symmetrical patternalso reduces the perception of any associated discomfort when theabsorbent article 100 is removed from the body.

The thickness in the z-direction of the gel composition influences theabsorptive capacity of the composition with thicker compositions beinggenerally capable of absorbing more fluid than thinner compositions.

In one embodiment, the skin-adhesive and absorbent gel composition 121of the absorbent article 100 is defined by a central portion 147 and aperipheral portion 145 (FIG. 3). The peripheral portion 145 which, insome embodiments, surrounds and is proximate to the vulva area andpossibly the pubic and perinea regions of the wearer may be moreadhesive to the skin of the wearer than the central portion 147. Thecentral portion 147 which, in some embodiments, is more likely tocontact bodily fluids including, for example, menses and urine, may bemore absorbent than the peripheral portion 145. The central portion 147may also contain apertures, perforations and/or pores for directingfluid inward into the gel composition 121. The peripheral portion 145may extend to the edge of the substrate 114 without departing from thescope of the present disclosure.

The gel composition 121 may be a single layer or may be multiple gellayers (not shown) which aid in skin-adhesion and/or capturing andholding of bodily fluid. In one embodiment, the gel composition has asubstrate-adjacent layer and a body-facing layer. The substrate-adjacentlayer may be more hydrophilic than the body-facing layer to help drawfluids away from the skin of the wearer and to the portions of the gelcomposition 121 furthest from the skin of the wearer.

The surface of the skin-adhesive and absorbent gel composition 121 maybe modified to produce different nanostructures and/or microstructuresat the surface of the composition. The surface may be manipulated tochange the thermodynamic, chemical and/or biological interaction of thegel composition 121 with the skin. For example, the surface may bemodified to reduce the adhesive pull-off force with the skin or bemodified to act as a basement membrane of scaffold for skin health andtissue regeneration. An example of a modification of the surface of apolymer adhesive is described in Mahdavi et al., “A Biodegradable andBiocompatible Gecko-inspired Tissue Adhesive,” PNAS, vol. 105: 7, pp.2307-2312, the entire contents of which are incorporated herein for allrelevant and consistent purposes.

In one embodiment, the skin-adhesive and absorbent gel composition 121is a coating that covers the individual threads of a nonwoven substrate114. The gel composition coating may be applied by coating the targetportions of the nonwoven substrate with a gel precursor composition andinitiating polymerization as more fully described below. The thicknessof the coating may be varied throughout the thickness of the nonwovensubstrate. For example, the coating of the gel composition 121 upon thethreads of the nonwoven substrate may be thicker near the portion of thegarment-facing surface of the absorbent article 100 with the thicknessgenerally decreasing toward the body-facing surface of the article tohelp draw fluid away from the skin of the wearer.

The absorbent article 100 may contain fluid-modifying components in thesubstrate 114 or the gel composition 121. Such fluid-modifyingcomponents include anti-fouling agents that prevent attachment of theabsorbed bodily fluids to the fibrous network (more fully describedbelow) within the absorbent article. Such anti-fouling agents preventthe pores of the article 100 from becoming plugged and allow the articleto be worn for a longer period of time without replacement. Anotherexample of a fluid-modifying component is a coagulant which causes theabsorbed fluid to coagulate and/or thicken when contacted with thecoagulant. Typically the coagulant is located near the garment-facingsurface of the article rather than near the body-facing surface of thearticle in order to “lock” absorbed fluids away from the skin and givethe wearer a sensation of dryness. Coagulants include, for example,psyllium husk, zeolites, chitosan and polysaccharides.

The absorbent article 100 may contain a superabsorbent material whichincreases the ability of the gel composition 121 to absorb a largeamount of fluid in relation to its own weight. Generally stated, thesuperabsorbent material can be a water-swellable, generallywater-insoluble, polymeric absorbent material, which is capable ofabsorbing at least about 15, suitably about 30, and possibly about 60times or more its weight in physiological saline (e.g., saline with 0.9wt % NaCl).

The absorbent article 100, including the substrate 114 and gelcomposition 121, should be sufficiently malleable and/or elastic suchthat the article conforms to the contours of the body as the wearermoves during a daily routine. The gel composition 121 should be able toconform to differing vulva dimensions and to the presence of public hairsuch that the gel composition provides a continuous fluid-impermeableseal. The measure of conformability may be determined and measured asdescribed in U.S. Patent Publication No. 2004/0116883, the contents ofwhich are incorporated herein be reference for all relevant andconsistent purposes. In one embodiment, the gel composition 121 has agap-protrusion area of at least about 20 mm² and, in another embodiment,at least about 40 mm².

Utilization of a Perforated Liner

Referring now to FIGS. 4 and 5, in one embodiment, the absorbent article100 includes an absorbent core 122 and a perforated liner 123. Theperforated liner 123 may be placed between the absorbent core 122 andthe body of the wearer such that the absorbent core 122 is between theperforated liner 123 and the substrate 114. In this arrangement, fluidpasses through the perforations of the perforated liner 123 and isabsorbed in the absorbent core 122. Because the liner 123 separates theabsorbed fluid from the skin of the wearer, the absorbent articleprovides a sensation of dryness to the wearer.

The absorbent core 122 may include any material that generally absorbsbodily fluids and, in one embodiment, includes an absorbent gelcomposition. In one particular embodiment, the absorbent core 122includes an absorbent hydrogel composition and, in another embodiment,comprises an aerogel composition. Hydrogel and aerogel compositions aremore fully described below.

The perforated liner 123 may be perforated according to any methodsknown in the art including, for example, a series of slits or a seriesof holes sized and adapted to allow bodily fluids (for example, menses)to pass. The perforated liner 123 may be constructed of many materialsand, for example, may be a polymeric film, a woven fabric, a nonwovenfabric or the like, as well as combinations or composites thereof.Optionally, the perforated liner 123 may be formed from one or morematerials. The perforated liner 123 should be able to manage differentbody excretions depending on the type of product. In feminine careproducts, often the perforated liner 123 must be able to handle mensesand urine. In addition, the perforated liner 123 may be comfortable,soft and friendly to the wearer's skin. In the present disclosure, theperforated liner 123 may include a layer constructed of any operativematerial, and may be a composite material. For example, the perforatedliner 123 may include a woven fabric, a nonwoven fabric, a polymer film,a film-nonwoven fabric laminate or the like, as well as combinationsthereof. Examples of a nonwoven fabric useable in the perforated linerinclude, for example, an airlaid nonwoven web, a spunbond nonwoven web,a meltblown nonwoven web, a bonded-carded web, a hydroentangled nonwovenweb, a spunlace web or the like, as well as combinations thereof. Otherexamples of suitable materials for constructing the perforated liner 123can include bonded-carded webs of polyester, polypropylene,polyethylene, nylon, or other heat-bondable fibers, finely perforatedfilm webs, net-like materials, and the like, as well as combinationsthereof. These webs can be prepared from polymeric materials such as,for example, polyolefins, such as polypropylene and polyethylene andcopolymers or biocomponent or biconstituent fibers thereof, polyestersin general including aliphatic esters such as polylactic acid, nylon orany other heat-bondable materials. Some minor amount ofnon-thermoplastic fibers (less than 50% by weight) such as rayon orlyocell may be blended with the heat-bondable fibers.

In one embodiment, the perforated liner 123 is a hydrophobic material oris a material that is less hydrophilic than the material of theabsorbent core 122. In another embodiment, the perforated liner 123 is ahydrophobic silicone gel.

Other examples of suitable materials for the perforated liner 123 arecomposite materials of a polymer and a nonwoven fabric material. Thecomposite materials are typically in the form of integral sheetsgenerally formed by the extrusion of a polymer onto a nonwoven web, suchas a spunbond material. In a particular arrangement, the perforatedliner 123 may be configured to be operatively liquid-permeable withregard to the liquids that the article is intended to absorb orotherwise handle. The operative liquid-permeability may, for example, beprovided by a plurality of pores, perforations, apertures or otheropenings, as well as combinations thereof, which are present or formedin the liner or body contacting layer. The apertures or other openingscan help increase the rate at which bodily liquids can move through thethickness of the liner or body contacting layer and penetrate into theother components of the article (e.g. into the absorbent core 122). Theselected arrangement of liquid permeability is desirably present atleast on an operative portion of the perforated liner 123 that isappointed for placement on the body side of the article. The perforatedliner 123 can provide comfort and conformability, and can function todirect bodily exudates away from the body and toward the absorbent core122. The perforated liner 123 can be configured to retain little or noliquid in its structure, and can be configured to provide a relativelycomfortable and non-irritating surface next to the skin of a wearer. Inthe present disclosure, the perforated liner 123 positioned over theabsorbent core 122 may have a surface which is embossed, printed orotherwise imparted with a pattern.

In one embodiment, the perforated liner 123 is sized and shaped to coverthe vulva region of a wearer. This allows a portion of the absorbentcore 122 to not be covered by the liner 123. The portion of the core 122not covered by the liner 123 may be utilized to adhere the absorbentarticle to the wearer.

Additional layers or substrates, including for example, a liquidacquisition and distribution layer (not shown), also referred to as asurge or transfer layer, and an optional tissue layer may also beincorporated into the absorbent product 100, for example, between theperforated liner 123 and the absorbent core 122. The distribution layermay be shorter than the absorbent core or have the same length as theabsorbent core 122. The distribution layer serves to temporarily hold aninsulting fluid to allow the absorbent core 122 sufficient time toabsorb the fluid, especially when a superabsorbent material is present.

Skin-Adhesive and Absorbent Hydrogel Compositions

The present disclosure makes provision for gel compositions for bothabsorbing bodily fluids and for bonding a substrate, such as anabsorbent article, to skin. These multi-functional gel compositionsallow the article to better move with the body allowing for superiorleak protection and result in a reduction in gapping between thematerial and the body of the wearer thus increasing fluid intercept andreducing the potential for fluid leak.

The gel compositions described herein may be suitable for use as theskin-adhesive and absorbent gel composition 121 illustrated in FIGS. 1-3and as the absorbent material of the absorbent core 122 illustrated inFIGS. 4 and 5. While the gel composition of the absorbent core 122 neednot be skin-adhesive as skin-adhesion may be provided by the liner 123,the gel composition of the absorbent core may be adhesive and absorbentwithout departing from the scope of the present disclosure. Descriptionsherein relating to “skin-adhesive and absorbent gel compositions” arealso applicable to “absorbent gel compositions” suitable for theabsorbent core 122 of the absorbent articles 100 illustrated in FIGS. 4and 5.

The skin-adhesive and absorbent gel compositions are generallycompatible with substrates and absorbent articles. Particularly, whiledescribed in terms of using the skin-adhesive and absorbent gelcomposition with an absorbent article, it should be recognized that theskin-adhesive and absorbent gel composition can be used with any of thesubstrates used for the components of the absorbent article, or anyother substrate known in the personal care art.

In one embodiment, the skin-adhesive and absorbent gel composition is ahydrogel (synonymously “hydrogel composition”). The hydrogel may be apolymerization reaction product of a hydrogel precursor composition asdescribed in U.S. patent application Ser. No. 11/709,996, which isincorporated herein for all relevant and consistent purposes.

The hydrogel composition may suitably be any color and, in oneembodiment, may be a clear gel solution. Clear gel solutions contain anabsence of precipitates or a limited amount of precipitates and aredemonstrated when there is no residue or precipitates visible in theformulation with the naked or unaided eye.

In one embodiment, the hydrogel composition is formed from a precursorcomposition that includes a monomer, initiator, cross-linking agent andsolvent. While any suitable monomer may be used, exemplary functionalmonomers include N-vinyl pyrrolidone (NVP), hydroxyethyl methacrylate(HEMA), methacrylic acid (MA) or its salt, styrene sulfonic acid (SSA)or its salt, potassium sulfopropyl acrylate (KPSA), dimethyl acrylamide(DMA), dimethyl amino ethyl methacrylate (DMAEMA) or its quaternary saltderivative, acrylamido methyl propane sulfonic acid (AMPS) or its salt,and the combination of any of the above. Additionally, the acid and saltof an exemplary functional monomer may be included in the hydrogel. Inone embodiment, the hydrogels are made from various classes of monomersincluding acrylates, vinyls, amides, esters, etc, of which can beelectrically neutral, cationic or anionic. Monomers may also be combinedto achieve desired adhesion and/or absorbent properties.

In one particular embodiment, acrylamido methyl propane sulfonic acid(AMPS), or its salt, is used as the hydrogel monomer, either alone or incombination with another comonomer. Generally, AMPS is highlyhydrophilic, is easy to work with, and polymerizes relatively easily.Also, AMPS, as a monomer, has a relatively favorable safety profile. Assuch, AMPS or its salt may be suitable for large scale production of ahydrogel precursor composition.

In one embodiment, the hydrogel is a cationic acrylate hydrogel. Acationic acrylate hydrogel suitable for use will generally be somewhatclear in color, viscous, and tacky to the touch. The hydrogel tends tobe sufficiently adhesive to a subject's skin, yet sufficiently cohesiveto be easily removable from the subject's skin and separable fromitself. Examples of specific desirable cationic acrylates are:acryloyloxyethyltrimethyl ammonium chloride which is readily availablefrom CPS Chemical Co. (New Jersey) or Allied Colloid (U.K.);acryloyloxyethyltrimethyl ammonium methyl sulfate which is alsoavailable from CPS Chemical Co. or Allied Colloid; and,acrylamidopropyltrimethyl ammonium chloride, which is available fromEvonik Degussa (Germany). A process for making hydrogels with theseexemplary acrylates is described in detail below.

In one embodiment, the monomer is from about 10% to about 80% by weightof the composition and, in another embodiment, from about 40% to about75% by weight of the composition and even from about 50% to about 75% byweight of the composition.

The hydrogel compositions may be formed by in-situ free radicalpolymerization of a water soluble monomer in the presence of water,desirably by ultra-violet curing with at least one initiator,multi-functional cross-linking agent(s), and a solvent. For example, anappropriate acrylate monomer, water, electrolyte (e.g. sodium sulfate),initiator or catalyst (e.g., 1-hydroxycyclohexylphenol ketone, etc.),multi-functional cross-linker (e.g., methylene-bis-acrylamide, etc.),and solvent (e.g., dimethyl sulfoxide) are combined, placed in a mold,and exposed to an appropriate amount of ultra-violet radiation.

The hydrogel monomer can also be combined with at least one co-monomerto form the hydrogel precursor composition. Examples of co-monomerswhich may be used include co-monomers soluble in water and, even moredesirably, include anionic co-monomers. In one embodiment, the amount ofco-monomer to be used may be in the range of about 5 to about 50% byweight, desirably about 10 to about 30% by weight, based on the amountof reactants used. Examples of suitable co-monomers include unsaturatedorganic carboxylic acids such as acrylic acid, methacrylic acid, maleicacid, itaconic acid, and citraconic acid and salts thereof, unsaturatedorganic sulfonic acids such as styrene sulfonic acid, methallyl sulfonicacid, 2-sulfoethyl acrylate, 2-sulfoethyl methacrylate, 3-sulfopropylacrylate, 3-sulfopropyl methacrylate, acrylamido-methylpropane sulfonicacid and salts thereof, N,N-dimethylacrylamide, vinyl acetate, otherradically polymerizable ionic monomers containing a carbon-carbon doublebond, and non-N-vinyl lactam co-monomers useful with N-vinyl lactammonomeric units such as N-vinyl-2-pyrrolidone, N-vinyl-2-valerolactam,N-vinyl-2-caprolactam, and mixtures thereof. Among the ionic monomersenumerated above, particularly desirable selections are3-sulfopropylacrylate or methacrylate, and salts thereof. Anotherdesirable selection is 2-acrylamido-2-methyl propane sulfonic acid andsalts thereof. Examples of cations involved in the formation of suchsalts include sodium, potassium, lithium, and ammonium ions. Ionicmonomers may be used singly or in a mixture of two or more monomers.

Any suitable solvent may be used. The desirability of a specific solventand/or the amount thereof may vary or depend in part on the othercomponents and quantities thereof selected to make up the hydrogelprecursor composition. The use of any solvent capable of dissolving theinitiator up to an amount equal to the initiator's solubility limit isdesired. In some embodiments, the solvent is an organic solvent such as,for example, dimethyl sulfoxide and glycerine. In other embodiments,water is the solvent used in the hydrogel precursor composition.

The solvent is adapted to dissolve the initiator (hydrophobic orhydrophilic) and is water soluble. The solvent may be adapted todissolve hydrophobic additives such as lipids, anti-oxidants, drugs, andfragrances. Additionally, the solvent may be adapted to dissolve skinbenefit agent(s) described below.

In one embodiment, the solvent is present in an amount up to about 20%by weight of the hydrogel precursor composition and, in anotherembodiment, from about 0.5% to about 5% by weight of the hydrogelprecursor composition.

The hydrogel precursor composition may also include a solubilizer toenhance the polymerization of the monomer, crosslinker, and/orinitiator, such as described in U.S. Pat. No. 7,045,559, which isincorporated herein for all relevant and consistent purposes. Anysuitable solubilizer or combination of solubilizers is contemplated. Thedesirability of a specific solubilizer and/or the amount thereof whichis included in hydrogel precursor composition may vary or depend in parton the other components and quantities thereof selected to make up thehydrogel precursor composition. Exemplary solubilizers include, forexample, cyclodextrin, cyclodextrin derivatives, and hydrotropes.Specific exemplary cyclodextrin derivative solubilizers include, forexample, hydroxypropyl β-cyclodextrin (HP-β-CD) (available from CargillDow, Minnetonka, Minn.), γ-cyclodextrin (γ-CD) (available from WackerBiochem Corporation, Adrian, Mich.) and other polymerizable cyclodextrinderivatives such as methacryloyl cyclodextrin. In a particularembodiment, the solubilizer is dimethyl sulfoxide (DMSO). In anotherparticular embodiment, the solubilizer is glycerin. In one embodiment,the solubilizer is present up to about 20% by weight of the hydrogelprecursor composition and, in another embodiment, between about 0.5% toabout 5% by weight of the hydrogel precursor composition.

The hydrogel composition may include an optional buffer system to helpcontrol the pH, prevent discoloration (for example, to prevent yellowingof the hydrogel), and/or prevent breakdown due to an extended presenceof water (i.e., hydrolysis). The use of a buffer system with thehydrogel composition is desired to provide the hydrogel with acommercially suitable shelf-life (i.e., a shelf-life of over one year)without discoloration. Suitable buffers include, but are not limited to,conventional buffers such as sodium hydroxide, sodium potassiumtartarate, and/or sodium phosphate monobasic, all of which arecommercially readily available from Aldrich Chemical Co., Inc.,Milwaukee, Wis. The pH of the hydrogel composition may be adjusted asdesired. In one embodiment, the compositions includes sufficient bufferto maintain the pH of the hydrogel in a range of about 3 to about 8.5,and, in another embodiment, from about 5.5 to about 7. In oneembodiment, a buffer is present in the hydrogel precursor composition inan amount up to about 10% by weight, and, in another embodiment, fromabout 0 to about 5% by weight of the hydrogel precursor composition.

As an alternative to the use of conventional buffers, an amount of theacidic form of the monomer used may be used in the hydrogel precursorcomposition to adjust the pH of the hydrogel composition. An amount ofthe acidic form of the monomer will be combined with the salt of themonomer so that an additional conventional buffer may not be needed. Inthis regard, pH is conventionally adjusted in hydrogels by utilizing adual buffer system including a non-monomeric acidic salt such as analuminum potassium sulfate and an additional buffer having a pH greaterthan 7 such as sodium hydroxide. For example, conventionally, aluminumpotassium sulfate, or another non-monomeric acidic salt, is added to thehydrogel precursor composition in an amount to stabilize the resultingpolymer, however, the amount utilized may result in an unacceptable dropin pH. Because of this drop in pH, sodium hydroxide, or another bufferhaving a pH greater than 7, is added to the hydrogel precursorcomposition to bring the pH up to a satisfactory level.

Additionally, an acidic salt may be used by itself, and not as part of adual buffer system, to maintain the pH in the desired range. However,utilizing the salt of the monomer in conjunction with the acid (as a pHadjuster) eliminates potential problems such as buffer incompatibilitywith the monomer while still increasing shelf life and stability of themonomer solution.

Other additives may be added such as, for example, skin benefit agentsas described below. These other additives may be included either beforeor after a curing step. The appropriateness of such additives isgenerally dependent upon the intended end use of the particularhydrogel. Any suitable additive or combination of additives such asthose suggested above or below is contemplated. The specific additiveand/or the amount thereof which is included may vary or depend in parton the other components and quantities thereof selected to make up thehydrogel.

The skin benefit agent may optionally not be present in the hydrogel butmay act as a separate hypoallergenic layer in communication with thehydrogel in order to reduce skin irritation of the wearer.

Initiators may be used in the polymerization of the hydrogel precursorcompositions described herein. Examples of initiators which may be usedinclude IRGACURE 184 (1-hydroxycyclohexyl phenyl ketone), IRGACURE 2959(4-(2-hydroxyethoxy)phenyl-(2-hydroxy-2-methylpropyl)ketone)), andDAROCUR 1173 (2-hydroxy-2-methyl-1-phenyl-propan-1-one), allcommercially available from Ciba Specialty Chemicals. These ultravioletUV initiators are non-yellowing. Additional examples of suitableinitiators (which may be photo initiators or thermal initiators) mayinclude benzoyl peroxide, azo-bis-isobutyro-nitrile, di-t-butylperoxide, bromyl peroxide, cumyl peroxide, lauroyl peroxide, isopropylpercarbonate, methylethyl ketone peroxide, cyclohexane peroxide,tutylhydroperoxide, di-t-amyl peroxide, dicumyl peroxide, t-butylperbenzoate, benzoin alkyl ethers (such as benzoin, benzoin isopropylether, and benzoin isobutyl ether), benzophenones (such as benzophenoneand methyl-o-benzoyl benzoate), acetophenones (such as acetophenone,trichloroacetophenone, 2,2-diethoxyacetophenone,p-t-butyltrichloro-acetophenone, 2,2-dimethoxy-2-phenyl-acetophenone,and p-dimethylaminoacetophenone), thioxanthones (such as xanthone,thioxanthone, 2-chlorothioxanthone, and 2-isopropylthioxanthone), benzyl2-ethyl anthraquinone, methylbenzoyl formate,2-hydroxy-2-methyl-1-phenylpropane-1-one,2-hydroxy-4′-isopropyl-2-methyl propiophenone, α-hydroxy ketone,tetramethyl thiuram monosulfide, allyl diazonium salt, and combinationsof camphorquinone and ethyl 4-(N,N-dimethylamino)benzoate. Othersuitable initiators may be found in, for example, Berner, et al., “PhotoInitiators—An Overview”, J. Radiation Curing (April 1979), pp. 29.

Although only one initiator is typically used in the hydrogel precursorcomposition, the composition may contain one or more second initiators.The one or more second initiators can be photo or chemical initiators.

In one embodiment, the amount of initiator is from about 0.01% to about5% by weight of the hydrogel precursor composition and, in anotherembodiment, from about 0.05% to about 2% by weight of the hydrogelprecursor composition and, in yet another embodiment, from about 0.1% toabout 0.5% by weight of the hydrogel precursor composition. Where one ormore second initiators are present, the amount of one or more secondinitiators in some embodiments is from about 0.01% to about 5%, fromabout 0.05% to about 2% or from about 0.1% to about 0.5% by weight ofthe hydrogel precursor composition. Where multiple initiators arepresent, it is preferred that the combined amount of the initiators beabout 5% or less by weight of the hydrogel precursor composition and, inanother embodiment, from about 0.02% to about 5% by weight of thehydrogel precursor composition.

UV curing parameters that achieve desired polymer properties areconventional and within the skill of the skilled artisan. A photoinitiator tends to operate by absorbing select wavelengths of UV toproduce radical initiating species to induce monomer polymerization. Thewavelengths and curing area set the style of UV bulb used in the curingprocess. Inhibition of polymerization due to dissolved oxygen, monomerinhibitors, or other radical scavenging moieties may be overcome bychanging the power, by pulsing, and/or by using initiator accelerators.

Each photo initiator is typically responsive to a specific or narrowwavelength range of UV light. In one embodiment of the presentdisclosure, two or more photo initiators are included in a hydrogelprecursor composition. The addition of more than one initiator in ahydrogel precursor composition allows for a broader range of the energyor range of wavelengths emitted by a UV source to be utilized. Theutilization of multiple initiators can further reduce solubility limitconcerns and related compatibility concerns, as more efficientpolymerization may be able to be achieved with two initiators present ina hydrogel precursor composition than with either of the initiators usedalone at the same overall initiator concentration.

The synergistic effect of initiators has not been previously identifiedor exhibited in previous hydrogels which incorporated one photoinitiator, if any initiator at all. It is further believed that theinclusion of initiators having different rates of initiation and/or theinclusion of initiators which begin initiation of polymerization of themonomer at different times relative to each other (such as that whichmay be experienced by multiple initiators (e.g., a thermally activatedchemical initiator (TACI) and a photo initiator)) contributes to ahigher yielding polymerization. That is, for example, where two photoinitiators are included, one may have a lower UV wavelength trigger andmay be more energetic (providing for a faster rate of initiation andreaction) than the other initiator which is triggered by a higher UVwavelength or range. The faster initiator may also die or be consumedfaster than the other. It is contemplated that it may be advantageous tohave polymerization occur at different rates and/or at a mixed ratewhich may not be obtainable with one initiator or with an initiatorwhich is suitable for a particular hydrogel precursor composition. Anexample of initiators which are not triggered or activatedsimultaneously, includes utilization of a photo initiator and a TACI inthe hydrogel precursor composition wherein the photo initiator istriggered by a UV source and reacts with the monomers in the precursorcomposition so as to generate heat to trigger the TACI.

While numerous combinations and variations of initiators are possible,it is believed that the combination of multiple initiators provides morefavorable kinetics which affords a higher probability of more extensivepolymerization of the monomer and/or other monomeric residues.

In one embodiment, a TACI is included in the hydrogel precursorcomposition to take advantage of the benefits of multiple initiatorpolymerization. As some heat is necessary to trigger a TACI, it iscontemplated that a TACI will generally be included only where heat willbe present in or produced in the hydrogel precursor composition in asufficient amount to trigger the TACI. As radical polymerizationreactions induced by photo initiators are known to be exothermic andthus to generate heat in response to UV exposure, TACI may be includedin a hydrogel precursor composition where a photo initiator is alsopresent so as to allow the TACI to take advantage of the heat generatedby the radical polymerization reaction induced by a photo initiator. Itis also contemplated that a TACI can be included where multiple photoinitiators are present. The presence of multiple photo initiatorsprovides for the potential benefits of multiple initiators discussedabove yet also provides for the triggering of a TACI where the heatgenerated by one photo initiator may be insufficient to trigger or fullytrigger the TACI (depending on the photo initiators and the TACIinvolved), whereby the TACI can further promote or complete thepolymerization of the functional monomer and other monomeric residues ina hydrogel precursor composition. Multiple TACIs may also be used.

Cross-linking agents may be used to cross-link the hydrogels.Multi-functional cross-linking agents which may be used include, forexample, methylene-bis-acrylamide and diethylene glycol diacrylate whichare both commercially available from Polysciences, Inc., Warrington, Pa.Other cross-linking agents which may be used include poly(ethyleneglycol) diacrylate, triethylene glycol-bis-methacrylate, ethyleneglycol-bis-methacrylate, ethylene glycol-dimethacrylate, bisacrylamide,triethyleneglycol-bis-acrylate,3,3′-ethylidene-bis(N-vinyl-2-pyrrolidone), trimethylolpropatetrimethacrylate, glycerol trimethacrylate, polyethylene glycoldimethacrylate, and other multifunctional polyacrylate andpolymethacrylate crosslinkers.

In one embodiment, the amount of cross-linking agent present in thehydrogel precursor composition is from about 0.01% to about 2% by weightof the hydrogel precursor composition and, in another embodiment, fromabout 0.05% to about 0.5% by weight of the hydrogel precursorcomposition.

Regardless of the technique utilized, crosslinking forms a hydrogelconstituted by a three-dimensional network that is substantiallywater-insoluble. Upon absorbing water, the hydrogel swells, therebyincreasing the area between crosslinks to form pores. For example, atits highest water content, the hydrogel may possess pores having anaverage size of from about 1 nanometer to about 10 microns, in someembodiments from about 10 nanometers to about 1 micron, and in someembodiments, from about 50 nanometers to about 100 nanometers. Thus,when exposed to water, the hydrogel does not dissolve, but instead mayabsorb a certain amount of water. Thus, the hydrogel composition iscapable of absorbing bodily fluids.

In some embodiments, at least one surfactant is included in the hydrogelprecursor composition or added to the hydrogel. It is believed that thepresence of a surfactant can increase the rate of absorbency of waterand moisture of the hydrogel. Exemplary surfactants include, forexample, alkyl polyglycosides; silicones modified to contain alkyl,polyglycol, and/or amino groups (e.g., ethyoxylated polydimethylsiloxanes); alkylphenol ethoxylate surfactant; and the like.Commercially available examples of suitable alkyl polyglycosides includeGlucopon 220, 225, 425, 600 and 625, all available from CognisCorporation. These products are all mixtures of alkyl mono- andoligoglucopyranosides with alkyl groups based on fatty alcohols derivedfrom coconut and/or palm kernel oil. Glucopon 220, 225 and 425 areexamples of particularly suitable alkyl polyglycosides. Glucopon 220 isan alkyl polyglycoside which contains an average of 1.4 glucosylresidues per molecule and a mixture of 8 and 10 carbon alkyl groups(average carbons per alkyl chain-9.1). Glucopon 225 is a related alkylpolyglycoside with linear alkyl groups having 8 or 10 carbon atoms(average alkyl chain-9.1 carbon atoms) in the alkyl chain. Glucopon 425includes a mixture of alkyl polyglycosides which individually include analkyl group with 8, 10, 12, 14 or 16 carbon atoms (average alkylchain-10.3 carbon atoms). Glucopon 600 includes a mixture of alkylpolyglycosides which individually include an alkyl group with 12, 14 or16 carbon atoms (average alkyl chain 12.8 carbon atoms). Glucopon 625includes a mixture of alkyl polyglycosides which individually include analkyl group having 12, 14 or 18 carbon atoms (average alkyl chain 12.8carbon atoms). Another example of a suitable commercially availablealkyl polyglycoside is TL 2141, a Glucopon 220 analog available fromICI. BASF Corporation offers MASIL silicones that are modified tocontain alkyl, polyglycol, amino groups, which may be included in thehydrogel precursor composition. For instance, MASIL SF-19 is a modifiedsilicone glycol.

The hydrogel composition may be used in sheet form as the absorbent gelcomposition 121 of the absorbent article 100 illustrated in FIGS. 1-3 oras the material of the absorbent core 122 of the absorbent article 100illustrated in FIGS. 4 and 5. The hydrogel composition may also be inparticulate form when used as the absorbent core 122 of the absorbentarticle 100 illustrated in FIGS. 4 and 5. In one embodiment, thehydrogel composition 121 includes an adhesive gel composition withhydrogel particulate mixed therein.

The hydrogel composition may be intertwined into a fibrous web toenhance the mechanical properties of the hydrogel as described in U.S.patent application Ser. No. 11/513,831, which is incorporated herein forall relevant and consistent purposes. The web may act as a scaffold orsupport matrix that enhances the rigidity of the skin-adhesive andabsorbent gel composition, especially under wet conditions. Also, theweb can provide a fiber structure, pore size, and pore distribution thatachieves a tailored handling of aqueous fluids. For example, a meltblownweb, which has a relatively small pore size, is useful for wicking awayand distributing an aqueous fluid over a large area, while a bondedcarded web is useful for applications when high fluid holding capacityis desired. Fluid handling capacity can be controlled by the relativehydrogel content in the hydrogel-fibrous web composite.

The hydrogel polymer may be integral with the fibers of the web. Forexample, the hydrogel polymer may be intertwined with the fibers of thewebs. As such, the hydrogel polymer cannot be easily separated from theweb and is effectively a permanent part of the structure of the web.Thus, the hydrogel allows the web to absorb water or moisture (includingwater vapor) to a much greater extent than the web alone. For instance,in one embodiment, the hydrogel polymer is integrated into a hydrophobicfibrous web that would not otherwise absorb any substantial amount ofwater or moisture, changing a relatively hydrophobic web to be water andmoisture absorbent.

In some embodiments, the hydrogel extends through the thickness of theweb. For example, the hydrogel may extend beyond the thickness of theweb. As such, the thickness of the web will be smaller than thethickness of the hydrogel. Without wishing to be bound by any particulartheory, it is believed that the skin-adhesive and absorption ability ofthe hydrogel-fibrous web composite can be enhanced by having thehydrogel extend beyond the thickness of the web, such that the exposedouter layer of the composite is primarily the hydrogel.

In order to integrate the hydrogel polymer into the fibrous web, thehydrogel precursor composition described above is allowed to saturatethe fibrous web before the composition is cured. The hydrogel polymer isthen polymerized from monomers that have been saturated and impregnatedwithin the fibrous web. Upon polymerization, the resulting hydrogelpolymer forms within the fibrous web, effectively integrating thehydrogel polymer within the fibers of the web. For instance, thehydrogel polymer may be intertwined with the fibers of the web. Also,the hydrogel polymer typically crosslinks with itself to form athree-dimensional polymer network that is integral to and intertwinedwith the fibers of the web. As such, the hydrogel polymer network isphysically integrated within the web and cannot be easily separated fromthe fibers of the web.

In some embodiments, depending upon the nature of the fibers of the web,the type of hydrogel polymer used, and the energy source used toinitiate polymerization, the hydrogel polymer may also have additionalchemical bonds or forces further attracting the hydrogel to the fibersof the web. For instance, the hydrogel polymer may crosslink with thefibers of the web, forming covalent bonds with the fibers of the web. Inother embodiments, other chemical forces, such as van-der-Waals forces,hydrogen bonding, ionic bonding, etc., further integrate the hydrogelpolymer to the fibers of the web.

The amount of hydrogel integrated into the fibrous web can be controlledby the amount of hydrogel monomer present in the hydrogel precursorcomposition. As such, controlling the amount of hydrogel in thecomposite web allows for control of the skin-adhesion properties of thecomposite web and the amount of water or moisture that can be absorbedby the composite web. Depending on the intended use of thehydrogel-fibrous web composite, the hydrogel can be present in thehydrogel-fibrous web composite at relatively high ratios. In someembodiments, the ratio of hydrogel to the fibrous web is at least about10:1, at least about 15:1, at least about 30:1, at least about 50:1 oreven at least about 100:1. In other embodiments the ratio of hydrogel tothe fibrous web is from about 1:1 to about 100:1, from about 5:1 toabout 100:1, from about 10:1 to about 100:1 or even from about 30:1 toabout 100:1.

Expressed in terms of basis weight, in some embodiments the hydrogel ispresent in the hydrogel-fibrous web composite at basis weights of fromabout 10 g/m² to about 1000 g/m², from about 50 g/m² to about 900 g/m²,from about 100 g/m² to about 800 g/m², from about 200 g/m² to about 700g/m², or even from about 300 g/m² to about 600 g/m².

The location of the hydrogel integrated within the web may be somewhatcontrolled by the wettability and structure of the web and the manner ofapplication of the hydrogel precursor composition to the web. Forinstance, application of the hydrogel precursor composition to only oneside of the web, and subsequent polymerization, can result in thehydrogel polymer being present mainly in that side of the web. Viscositymodifiers may also be added to increase the viscosity of the hydrogelprecursor composition to allow for controlled placement and formation ofthe hydrogel following polymerization.

As one skilled the art will recognize, any method of saturating and/orimpregnating the hydrogel precursor composition into the web may beused. For example, the hydrogel precursor formulation may be applied tothe fibrous web using any conventional technique, such as bar, roll,knife, curtain, foam, print (e.g., rotogravure), slot-die, drop-coating,or dip-coating techniques. For instance, the hydrogel precursorcomposition may be applied topically to the external surfaces of thefibrous web. In one particular embodiment, the hydrogel precursorcomposition is applied uniformly to one or both surfaces of the fibrousweb.

In one embodiment, the fibrous web is passed over a guide roll and intoa bath with the treatment time controlled by first and second guiderolls located within the bath. The nip between first and second squeezerolls downstream of the bath removes any excess hydrogel precursorcomposition which may be returned to the bath.

In other application techniques, where one desires to treat only asingle side, and not the inner layers or opposing side of the fibrousweb, other processes can be used, such as rotary screen, reverse roll,Meyer-rod, Gravure, slot-die, gap-coating, etc. However, even accordingto these application techniques, a sufficient amount of the hydrogelprecursor composition penetrates the web, allowing the hydrogel to beintegral to the fibers upon polymerization.

Regardless of the method of impregnation or saturation of the web, thehydrogel monomers saturated and/or impregnated within the web may bepolymerized, either before or after drying of the web, depending on thepolymerization initiation method. For instance, when a UV-initiator ispresent in the hydrogel precursor composition to initiate thepolymerization of the hydrogel monomers upon the application of UVradiation, the web may be passed under a UV lamp (not shown) for aspecific time allowing for the desired degree of polymerization, priorto drying the web. Then the web may be further dried, if needed, bypassing over dryer cans or other drying means and then wound between tworelease film or paper layers as a roll or converted to the use for whichit is intended. Alternative drying means include ovens, through airdryers, infra red dryers, air blowers, and the like.

Drying the hydrogel-fibrous web composite can control the water contentof the composite, which can affect the amount of water that the hydrogelcan absorb. In most applications, the water content of the hydrogel inthe hydrogel-fibrous web composite will be relatively low, which allowsfor more water and moisture to be absorbed by the hydrogel. In oneembodiment, the water content of the hydrogel in the hydrogel-fibrousweb composite is less than about 20% by weight and, in anotherembodiment, less than about 15% by weight. In other embodiments, thewater content of the hydrogel in the hydrogel-fibrous web composite willbe less than about 10% by weight, less than about 5% by weight or evenless than 2% by weight.

For example, the fibrous web may pass over a guide roll from a fibrousweb supply roll. The fibrous web is first impregnated or saturated withthe hydrogel precursor composition in a treatment center. Then, thetreated fibrous web may be combined with a first release layer suppliedfrom a release layer supply roll. The treated fibrous web is then curedin a curing station, such as, for example, by UV radiation. The fibrousweb may then be dried in a dryer, and combined with a second releaselayer supplied from a release layer supply roll. Finally, the treatedfibrous web sandwiched between the first release layer and the secondrelease layer can then be rewound on a roll.

It is also understood that the method of treatment of the fibrous webwith the impregnating hydrogel precursor composition may alsoincorporate other ingredients into the web such as the skin benefitagents described below. These other additives may be included eitherbefore or after a curing step. For instance, in some embodiments, theskin benefit agent may be present in the hydrogel precursor composition,which can help the additive become impregnated within the resultinghydrogel-fibrous web composite.

The hydrogel can be integrated into any suitable fibrous web, includingboth woven and nonwoven webs. In general, the intended end use of thecomposite web will dictate the composition and type of web utilized. Inone particular embodiment, the fibrous web is a porous fibrous web. Inthis embodiment, the porosity of the fibrous web allows the hydrogel topenetrate the pores of the web and for greater fluid transport of waterand moisture into the web, facilitating the ability of the integratedhydrogel to absorb the water and moisture. Also, in those applicationswhere comfort and breathability is desired, the porous fibrous web canbe breathable, allowing air to flow through the web, while moisture andwater are retained within the web. In other embodiments, porous filmsand foams can also be used in similar fashion as porous webs.

The nonwoven web may be a spunbond web, a meltblown web, a bonded cardedweb, or another type of nonwoven web, including natural and/or syntheticfibers, and may be present in a single layer or a multilayer compositeincluding one or more nonwoven web layers. When constructed of syntheticpolymers, a wide variety of thermoplastic polymers may be used toconstruct the nonwoven substrate, including without limitationpolyamides, polyesters, polyolefins, copolymers of ethylene andpropylene, copolymers of ethylene or propylene with a C₄-C₂₀ α-olefin,terpolymers of ethylene with propylene and a C₄-C₂₀ α-olefin, ethylenevinyl acetate copolymers, propylene vinyl acetate copolymers,styrene-poly(ethylene-α-olefin) elastomers, polyurethanes, A-B blockcopolymers where A is formed of poly(vinyl arene) moieties such aspolystyrene and B is an elastomeric midblock such as a conjugated dieneor lower alkene, polyethers, polyether esters, polyacrylates, ethylenealkyl acrylates, polyisobutylene, polybutadiene, isobutylene-isoprenecopolymers, and combinations of any of the foregoing. In some particularembodiments, polyolefins, such as polyethylene and polypropylenehomopolymers and copolymers, may be used to construct the nonwoven web.The webs may also be constructed of bicomponent or biconstituentfilaments or fibers. The nonwoven webs may have a wide variety of basisweights, preferably ranging from about 8 g/m² to about 120 g/m².

Particularly suitable nonwoven webs can be hydrophobic webs, such asthose including polyolefin fibers and polyester fibers. Meltblown andspunbond webs of polyolefin fibers such as, for example, polypropyleneand polyethylene, may be integrated with hydrogel polymers to change theotherwise hydrophobic web to a water absorbent web, withoutsubstantially affecting the other properties of the web.

The type of nonwoven web can dictate the function of the resultingcomposite hydrogel-fibrous web. For example, meltblown web, which hasrelatively small pore size, is useful for wicking away and distributingan aqueous fluid over a large area, while a bonded carded web is usefulfor applications when high fluid holding capacity is desired. Fluidhandling capacity can be controlled by the relative hydrogel content inthe hydrogel-fibrous web composite.

In some embodiments, the nonwoven web can be a composite nonwoven web,including but not limited to, coform webs, webs entangled with pulpfibers, etc. For instance, a suitable nonwoven composite web can be apolypropylene web entangled with pulp fibers, such as the fabric soldunder the name HYDROKNIT by Kimberly-Clark Corp., Inc. of Neenah, Wis.

In another embodiment, the web can be a woven web. For instance, certainapplications will typically involve woven webs of cotton, polyester,nylon, wool, and the like, and combinations thereof. For example, insome clothing applications, the fibrous web can be a woven web.

Additionally, the hydrogel-fibrous web composite can be combined withother webs to form a laminate. For instance, the hydrogel-fibrous webcomposite can be one or more layers of a spunbond-meltblown-spunbond(SMS) web.

Skin-Adhesive and Absorbent Aerogel Compositions

In one embodiment, the absorbent article 100 of FIGS. 1-3 contains askin-adhesive and absorbent gel composition 121 comprising an aerogel.Further, the material of the absorbent core of the article 100illustrated in FIGS. 4 and 5 may be an aerogel. Suitable aerogelsinclude inorganic, organic and carbon aerogels. Aerogels may be producedby polycondensation reactions or “sol-gel processes.”

Inorganic aerogels can be obtained by supercritical drying of highlycross-linked and transparent hydrogels synthesized by polycondensationof metal alkoxides. Silica aerogels are the most well known inorganicaerogels. Silica-based inorganic aerogels are typically derived usingprecursors or monomers such as tetramethyl orthosilicate (TMOS,Si(OCH₃)₄), tetraethyl orthosilicate (TEOS, Si(OCH₂CH₃)₄), combinationsof the foregoing orthosilicates, or the like. Inorganic aerogels may beproduced according to the methods described in U.S. Pat. No. 6,670,402and inorganic silica aerogels may be produced by the methods of U.S.Pat. No. 7,265,158, both of which are incorporated herein by referencefor all relevant and consistent purposes.

Organic aerogels may be synthesized by supercritical drying of the gelsobtained by the sol-gel polycondensation reaction of monomers such as,for example, resorcinol with formaldehyde, in aqueous solutions. Carbonaerogels can be obtained by pyrolizing the organic aerogels at elevatedtemperatures. Methods for producing organic aerogels and carbon aerogelsare described in U.S. Pat. No. 7,378,450, which is incorporated hereinby reference for all relevant and consistent purposes.

Organic aerogels may be produced by the reaction of any one or acombination of various monomers in an appropriate ratio withformaldehyde, furfural, or the like in the presence of a catalyst via apolymerization reaction (e.g., a polycondensation reaction). Themonomer(s) is preferably a polyhydroxybenzene compound, exemplaryembodiments of which include, for example, resorcinol, phenol, catechol,chloroglucinal, combinations thereof, and the like. Reaction of suchmonomers with formaldehyde or furfural generally produce, for example,resorcinol-furfural, resorcinol-formaldehyde,phenol-resorcinol-formaldehyde, catechol-formaldehyde,chloroglucinol-formaldehyde, or the like.

In one exemplary polymerization reaction to form an organic aerogel, thereactants (i.e., the monomers) are mixed with the catalyst to producethe aerogel in the form of a monolithic gel, which is then dried bysolvent exchange and extraction. The resulting organic aerogel may thenbe pyrolized in an inert atmosphere (e.g., nitrogen) to form a carbonaerogel. More specifically, the polymerization reaction is a sol-gelpolymerization of multifunctional organic monomers in a solvent (e.g.,water). The sol-gel polymerization leads to the formation of highlycross-linked, transparent or translucent gels (“hydrogel sols”). A metalmay also be added with the monomers, thereby forming an aerogel/metalliccomposite.

In a preferred sol-gel polymerization, one mole of resorcinol(1,3-dihydroxybenzene) condenses in the presence of a basic catalystwith two moles of formaldehyde. A mildly basic catalyst (e.g., sodiumcarbonate) is preferred. Resorcinol is a trifunctional monomer capableof receiving formaldehyde molecules the 2-, 4-, and/or 6-positions onits ring. The substituted resorcinol rings condense with each other toform nanometer-sized clusters in solution. Eventually, the clusterscrosslink through their surface groups (e.g., —CH₂OH) to form thehydrogel sol.

The size of the clusters may be regulated by the concentration ofcatalyst in the resorcinol-formaldehyde (RF) mixture. More specifically,the mole ratio of resorcinol (R) to catalyst (C) (R/C) controls thesurface area and electrochemical properties of the resulting gel.Preferably, the R/C ratio is about 50 to about 300. Other commonlyreferenced ratios include resorcinol (R) to formaldehyde (F) (R/F) andresorcinol (R) to water (W) (R/W). Typically, the R/F and R/W molarratios are each about 0.01 to about 10.

The hydrogel sol is then cured for a time and temperature sufficient tostabilize the aerogel structure and form a cured hydrogel. Curing timesrange from about 2 hours to about 5 days or more. Curing temperaturesrange from about 25 degrees centigrade (C) to about 150° C., Pressuresgreater than 1 atmosphere (atm) can be used to decrease the curing time.After curing, RF aerogels may be translucent and dark red or black incolor or substantially transparent.

The next step in organic aerogel preparation is to dry the curedhydrogel. If the polymerization solvent is removed from the gel bysimple evaporation, large capillary forces are exerted on the pores,thereby forming a collapsed structure, i.e., a xerogel. In order topreserve the gel skeleton and minimize shrinkage, it is preferable toperform the drying step under supercritical conditions (describedhereinafter). Other drying steps may also be conducted, if desired,usually before the supercritical extraction step. For example a solventexchange may be conducted in which the cured hydrogel is contacted withan exchange solvent, e.g., acetone, prior to subjecting the curedhydrogel to supercritical extraction to form the dried aerogel. Thesupercritical extraction may be performed with a supercritical fluid,such as liquid carbon dioxide. Also, as an alternative or in addition tothe exchange step, surfactants may be used to remove water from thecured hydrogel. The highly porous material obtained from this removaloperation is the organic aerogel. By appropriate adjustment of dryingconditions, a hybrid structure having characteristics of both a xerogeland an aerogel may be produced. For example, such a hybrid may beproduced as a result of a partial evaporation of the gel solvent underconditions promoting xerogel formation followed by evaporation of theremaining solvent under conditions promoting aerogel formation. Theresulting hybrid structure would then be dried under supercriticalconditions and pyrolized. Preparation of other xerogel-aerogel hybridsmay be produced by first evaporating under conditions promoting aerogelformation and completing the evaporation under xerogel-promotingconditions.

As noted above, one means for removing water from the cured hydrogel isby extraction under supercritical conditions. As used herein, a“supercritical fluid” (synonymously “supercritical solution” or“supercritical solvent”) is one in which the temperature and pressure ofthe fluid are greater than the respective critical temperature and ofthe fluid. A supercritical condition for a particular fluid refers to acondition in which the temperature and pressure are both respectivelygreater than the critical temperature and critical pressure of theparticular fluid.

A “near-supercritical fluid” is one in which the reduced temperature(actual temperature measured in Kelvin divided by the criticaltemperature of the solution (or solvent) measured in Kelvin) and reducedpressure (actual pressure divided by critical pressure of the fluid) ofthe fluid are both greater than 0.8 but the fluid is not a supercriticalfluid. A near-supercritical condition for a particular fluid refers to acondition in which the reduced temperature and reduced pressure are bothrespectively greater 0.8 but the condition is not supercritical. Underambient conditions, the fluid can be a gas or a liquid. The term fluidis also meant to include a mixture of two or more different individualfluid. As used herein, the term “supercritical fluid” and “supercriticalconditions” are intended to include near-supercritical fluids andnear-supercritical conditions respectively.

The temperature and pressure of the extraction process depend on thechoice of supercritical fluid. Generally, the temperature is less thanabout 250° C. and often less than about 100° C., while the pressure isabout 50 atm to about 500 atm.

Solvents that can be used as supercritical fluids are sometimes referredto as dense gases. Suitable solvents for use as supercritical fluidsinclude, for example, carbon dioxide, ethane, propane, butane, pentane,dimethyl ether, ethanol, water and mixtures thereof. Carbon dioxide is apreferred supercritical fluid for use in accordance with the presentinvention. For example, at 333 Kelvin (K) and 150 atm, the density ofCO₂ is 0.60 g/cm³; therefore, with respect to CO₂, the reducedtemperature is 1.09, the reduced pressure is 2.06, and the reduceddensity is 1.28. Carbon dioxide is a particularly good choice ofsupercritical fluid. Its critical temperature (31.1° C.) is close toambient temperature and thus allows the use of moderate processtemperatures (less than about 80° C.). The time required forsupercritical drying depends on the thickness of the gel.

In cases where the cured hydrogels are of sufficiently high density,such as greater than about 40 weight percent (wt %) solids, the porenetwork may have sufficient inherent strength to withstand the dryingprocess without resort to supercritical drying conditions. Thus, carbondioxide may be bled from the vessel under non-supercritical conditions.Non-supercritical drying is particularly attractive because of itsreduced processing time. To maximize crosslinking and further increasethe density of the gels, the cured hydrogel may be subjected to a curecycle.

Following the solvent exchange/extraction step and any cure cycle, theorganic aerogel may be pyrolized at elevated temperatures of about 400°C. to about 2,000° C. in an inert atmosphere of nitrogen, argon, neon,helium, or any combination of the foregoing gases to form a pyrolizedaerogel, e.g., a carbon aerogel. The pyrolysis temperatures can alterthe surface area and structure of the pyrolized aerogel. In particular,higher surface areas are achieved at lower temperatures. The resultingaerogels, independent of the procedure by which they are pyrolized, areblack and not transparent due to the visible absorption properties ofthe carbon matrix.

The aerogels of the present disclosure typically have a surface area offrom about 400 m²/g to about 2,000 m²/g, a pore volume of about 0.5cm³/g to about 10 cm³/g, and a density of about 0.01 g/cm³ to about 2.0g/cm³. Such properties can be readily determined by those skilled in theart. For example, surface area and pore volume can be determined by theBET method (the Brunauer, Emmett, and Teller method), and density can bedetermined by using a pycnometer.

Binders and/or fiber particles may be incorporated into the aerogel toproduce a more mechanically stable aerogel as described in U.S. Pat. No.6,887,563, which is incorporated herein by reference for all relevantand consistent purposes.

The aerogels may generally be utilized similar to the utilization ofhydrogels as described above. Particularly, the aerogels may possess thesame skin-adhesive and absorption properties and may include the samesurfactants, adhesion modifiers and/or skin benefit agents describedbelow.

Adhesion Modifiers

In accordance with the present disclosure, an adhesion modifier asdisclosed in U.S. application Ser. No. 12/267,806 may suitably beincluded in the gel composition 121 and/or the perforated liner 123. Theadhesion modifier may further allow the gel composition 121 and/or liner123 to maintain its bonding strength with the substrate, yet remaingentle on the skin's surface. It should be understood that an adhesionmodifier is optional and need be included in the absorbent article. Theadhesion modifier may also behave as a delivery vehicle or carrier thatcan aid in delivering one or more skin benefit agents to the skin of auser. For example, in one embodiment, the adhesion modifier is in theform of a matrix. The matrix-like adhesion modifier may include (i.e.,be filled with) at least one skin benefit agent as described below tofunction as a carrier for the skin benefit agent. The skin benefitagent-containing matrix may be dispersed within the gel composition.

Generally, the matrix-like adhesive modifiers are channel-like matricesor pore-like matrices. Specifically, the matrix is formed in themodifiers to contain “channels” or “pores” in which the skin benefitagents can be introduced. These types of adhesive modifiers serve a dualpurpose of: (1) modifying the adhesion of the skin-adhesive andabsorbent gel composition to the skin so that it can be adheredefficiently, but capable of releasing from the skin without damage tothe skin; and (2) allowing for a controlled release of the skin benefitagents to the skin of the user.

It should be understood that while numerous delivery vehicles are knownin the art, all delivery vehicles or carriers are not suitable for usein the skin-adhesive and absorbent gel compositions of the presentdisclosure. More particularly, the adhesion modifiers must be compatiblewith the gel composition to maintain flexibility and adhesive strengthof the composition without causing damage to the surface of the skin.

In one embodiment, the adhesion modifier(s) are added to the hydrogelprecursor composition described above. During polymerization, theadhesion modifier becomes suspended within the gel composition.

Suitable adhesion modifiers include, for example, colloidal particles,crosslinked copolymers, and combinations thereof. More particularly,colloidal particles well suited for use in the present disclosureinclude microcrystalline cellulose, fumed silica, silica, hydratedsilica, and combinations thereof. Commercially available colloidalparticles such as fumed silica (available as Cab-o-sil M5 from CabotCorporation, Tuscola, Ill.) and blends of microcrystalline cellulose andcellulose gum (available as AVICEL 591 from FMC Corporation,Philadelphia, Pa.) are particularly suitable for use as adhesionmodifiers.

In one particularly embodiment, the adhesion modifier may includepolymer-like network or matrix structure, such as cross-linked crosspolymers (for example, acrylate copolymers). Cross-linked acrylatecrosspolymers well-suited for use in the present disclosure includeallyl methacrylates crosspolymer, allyl methacrylate/glycoldimethacrylate crosspolymer, lauryl methacrylate/glycol dimethacrylatecrosspolymer and derivatives thereof. Suitable examples includePOLY-PORE E-200, POLY-PORE L-200, POLYTRAP 7603 and POLYTRAP 6603Adsorber which are all available from Amcol Health & Beauty Solutions(Arlington, Ill.). The POLY-PORE and POLYTRAP ingredients can be loadedwith skin beneficial ingredients prior to inclusion in the skin-adhesivecombination or are available pre-loaded from Amcol Health & BeautySolutions as POLYTRAP 6035 Cyclomethicone, POLYTRAP 7100 DimethiconeMacrobeads, POLYTRAP 6500 Dimethicone/Petrolatum Powder, POLYTRAP 665TO(which is loaded with tocopherol), and POLYTRAP 6038 Mineral OilMacrobeads.

In one embodiment, the skin-adhesive and absorbent composition includesfrom about 1% (by total weight composition) to about 50% (by totalweight composition) adhesion modifier and, in other embodiments, fromabout 2% (by total weight composition) to about 25% (by total weightcomposition) or from about 5% (by total weight composition) to about 20%(by total weight composition) adhesion modifier.

Skin Benefit Agents

In accordance with the present disclosure, skin benefit agents maysuitably be included in the gel composition 121, the absorbent core 122and/or the perforated liner 123. A skin benefit agent generally providesa skin benefit (e.g., functional, aesthetic, or heath benefit) to theuser/wearer. For example, a skin benefit agent such as an antiperspirantcan be beneficial to the skin-adhesive and absorbent gel composition asit will prevent the gel composition from weakening as a result ofincreased sweating in specific areas of the body for use with theskin-adhesive composition.

Exemplary skin benefit agents may include for example: antiperspirants,deodorants, skin moisturizers, humectants, pH modulators, soothingagents, antimicrobials, preservatives, film formers, and combinationsthereof. Antiperspirant agents are those active ingredients generallyfound in antiperspirant products. In the Final Rule for U.S.Antiperspirant Drug Products for Over-the Counter Human Use; FinalMonograph (68 Federal Register 34273-34293, Jun. 9, 2003) an“antiperspirant” refers to a drug product applied topically that reducesthe production of perspiration (sweat) at that site. See 21 CFR 350.3for definition and 21 CFR 350.10 for a listing of the U.S.Antiperspirant active ingredients. The following is a list ofingredients currently listed in the INCI Dictionary under this category:adipic acid/neopentyl glycol crosspolymer, aluminum chloride, aluminumchlorohydrate, aluminum chlorohydrex PEG, aluminum chlorohydrex PG,aluminum dichlorohydrate, aluminum dichlorohydrex PEG, aluminumdichlorohydrex PG, aluminum sesquichlorohydrate, aluminumsesquichlorohydrex PEG, aluminum sesquichlorohydrex PG, aluminum sulfate(aluminum sulfate buffered), aluminum zirconium octachlorohydrate,aluminum zirconium octachlorohydrex GLY, aluminum zirconiumpentachlorohydrate, aluminum zirconium pentachlorohydrex GLY, aluminumzirconium tetrachlorohydrate, aluminum zirconium tetrachlorohydrex GLY,aluminum zirconium trichlorohydrate, aluminum zirconium trichlorohydrexGLY, Bursera Graveolens fruit oil, ferric chloride, Humulus Lupulus(Hops) cone extract, Hypericum Perforatum flower/twig extract, zirconiumpowder, and combinations thereof. Particularly preferred antiperspirantsfor use in the skin-adhesive composition of the present disclosureinclude commercially available REACH Aluminum-Zirconium Complex (AZP)908, and REACH 103, which is a chlorohydrate, both of which arecommercially available from Reheis, Inc., Berkeley Heights, N.J.

Deodorants are agents that reduce or eliminate unpleasant odors andprotect against the formation of malodor on bodily surfaces. Absorbentscan act as deodorants if they have the ability to absorb malodorouschemicals. Also, chemical reactions can be used to destroy themalodorous substance in selected cases. Perfumes and the like can beused to mask the perception of malodor by the process of reodorization.Unpleasant odors, also may be the result of microbiological activity.Thus, cosmetic biocides are ingredients frequently used in skin-surfacedeodorants. The following listing of deodorants is limited to thoseingredients commonly used for this purpose: adipic acid/neopentyl glycolcrosspolymer, Alpinia Uraiensis stalk/leaf water, aluminum chloride,aluminum chlorohydrate, aluminum chlorohydrex, aluminum chlorohydrexPEG, aluminum chlorohydrex PG, aluminum dichlorohydrate, aluminumdichlorohydrex PEG, aluminum dichlorohydrex PG, aluminum lactate,aluminum phenolsulfonate, aluminum sesquichlorohydrate, aluminumsesquichlorohydrex PEG, aluminum sesquichlorohydrex PG, aluminumsulfate, aluminum triphosphate, aluminum zinc oxide, aluminum zirconiumoctachlorohydrate, aluminum zirconium octachlorohydrex GLY, aluminumzirconium pentachlorohydrate, aluminum zirconium pentachlorohydrex GLY,aluminum zirconium tetrachlorohydrate, aluminum zirconiumtetrachlorohydrex GLY, aluminum zirconium tetrachlorohydrex PEG,aluminum zirconium tetrachlorohydrex PG, aluminum zirconiumtrichlorohydrate, aluminum zirconium trichlorohydrex GLY, amber powder,ammonium phenolsulfonate, ammonium silver zinc aluminum silicate,benzalkonium bromide, benzalkonium cetyl phosphate, benzalkoniumchloride, benzalkonium saccharinate, benzethonium chloride, BoesenbergiaPandurata Rhizome extract, bromochlorophene, t-Butyl methylphenoxyphenol, calcium magnesium silicate, Callicarpa Macrophylia flowerextract, Candida Bombicola/glucose/methyl rapeseedate ferment, capryloylgold of pleasure amino acids, cetylpyridinium chloride,chlorophyllin-copper complex, chlorothymol, chloroxylenol, CitrusReticulata (Tangerine) peel oil, cloflucarban, colloidal platinum,Cuminum Cyminum seed extract, Curcuma Heyneana root powder,cyclopentadecanone, dequalinium chloride, dichlorophene,dichloro-m-xylenol, dimethicone/PEG-15 crosspolymer, dipotassiumcapryloyl glutamate, disodium capryloyl glutamate, disodiumdihydroxyethyl sulfosuccinylundecylenate, domiphen bromide,ethylhexylglycerin, fermented vegetable, hexachlorophene, hydrolyzedSasa Veitchil extract, ketoglutaric acid, lauryl isoquinolinium bromide,laurylpyridinium chloride, magnesium/aluminum/zinc/hydroxide/carbonate,mentha aquatica water, methylbenzethonium chloride, methyl undecylenate,Michelia Champaca flower oil, micrococcus/hydrolyzed nonfat milkferment, octadecenedioic acid, oligopeptide-10, Pandanus Amaryllifoliusleaf extract, Pelargonium Graveolens water, phenol, Phyllostachys Edulisstem extract, Piper Betle leaf oil, polyaminopropyl biguanide stearate,potassium capryloyl glutamate, Rosmarinus Officinalis (Rosemary) flowerextract, saccharomyces/persimmon fruit juice ferment extract,Saccharomyces/Rhodobacter/Lactobacillus/Leuconostoc/Streptomyces/Griseus/Aspergillus/Bacillusferment filtrate, Sasa Senanensis leaf extract, Sasa Senanensis leafpowder, silver copper zeolite, sodium bicarbonate, sodium capryloylglutamate, sodium phenolsulfonate, sodium silver aluminum silicate,Stemmacantha Carthamoides root extract, totarol, triclocarban,triclosan, tricyclodecenyl propionate, Urginea Maritima tuber extract,zeolite, zinc lactate, zinc phenolsulfonate, zinc ricinoleate, zincsilicate, and combinations thereof.

Humectants are hydroscopic agents that are widely used as skinmoisturizers. Their function is to prevent the loss of moisture from theskin and to attract moisture from the environment. Common humectantsinclude, for example, glycerin, butylene glycol, betaine, sodiumhyaluronate, and the like, and combinations thereof.

Soothing agents, also referred to as emollients, lubricate, sooth, andsoften the skin surface. Exemplary emollients include oily or waxyingredients such as esters, ethers, fatty alcohols, hydrocarbons,silicones, and the like, and combinations thereof.

Film formers, also referred to as skin barrier enhancers or occlusivematerials, increase the water content of the skin by blocking waterevaporation. These materials generally include lipids which tend toremain on the skin surface or hydrocarbons such as petrolatum and wax.

Rheology enhancers may help increase the melt point viscosity of theformulation so that the formulation readily remains on the surface ofthe substrate and/or laminated article and does not substantiallymigrate into the interior of the substrate, while substantially notaffecting the transfer of the formulation to the skin. The rheologyenhancers help the formulation to maintain a high viscosity at elevatedtemperatures, such as those encountered during storage andtransportation. Additionally, rheology enhancers can influence theoverall consistency and skin feel of the formulation.

Suitable rheology enhancers include combinations of alpha-olefins andstyrene alone or in combination with mineral oil or petrolatum,combinations of di-functional α-olefins and styrene alone or incombination with mineral oil or petrolatum, combinations ofalpha-olefins and isobutene alone or in combination with mineral oil orpetrolatum, ethylene/propylene/styrene copolymers alone or incombination with mineral oil or petrolatum, butylene/ethylene/styrenecopolymers alone or in combination with mineral oil or petrolatum,ethylene/vinyl acetate copolymers, polyethylene polyisobutylenes,polyisobutenes, polyisobutylene, dextrin palmitate, dextrin palmitateethylhexanoate, stearoyl inulin, stearalkonium bentonite,distearadimonium hectorite, and stearalkonium hectorite,styrene/butadiene/styrene copolymers, styrene/isoprene/styrenecopolymers, styrene-ethylene/butylene-styrene copolymers,styrene-ethylene/propylene-styrene copolymers, (styrene-butadiene) npolymers, (styrene-isoprene) n polymers, styrene-butadiene copolymers,and styrene-ethylene/propylene copolymers and combinations thereof.Specifically, rheology enhancers such as mineral oil andethylene/propylene/styrene copolymers, and mineral oil andbutylene/ethylene/styrene copolymers (Versagel blends from Penreco) areparticularly preferred. Also, Vistanex (Exxon) and Presperse (Amoco)polymers are particularly suitable rheology enhancers. Other suitableexamples of oil-soluble rheology enhancers include, but are not limitedto, aluminum stearate, aluminum tristearate, arachidyl alcohol,arachidyl tehenate, behenyl alcohol, C₈₋₂₂ alkyl acrylate/butyldimethicone methacrylate copolymer, C₁₂₋₂₂ alkylacrylate/hydroxyethylacrylate copolymer, C₁₈₋₃₈ alkyl, C₂₄₋₅₄ acidester, C₂₀₋₂₄ alkyl dimethicone, C₂₄₋₂₈ alkyl dimethicone, C₃₀₋₆₀ alkyldimethicone ceresin, cerotic acid, cetearyl alcohol, cetearyldimethicone/vinyl dimethicone crosspolymer, cetyl alcohol, cetyl glycol,dibehenyl fumarate, hydrogenated polyisobutene, hydrogenated oils,isocetyl alcohol, isocetyl stearoyl stearate, isophthalicacid/pentaerythritol crosspolymer benzoate/isostearate, isostearylalcohol, isostearyl stearoyl stearate, jojoba alcohol, lanolin alcohol,lanolin wax, neopentyl glycol dicaprate, neopentyl glycoldicaprylate/dicaprate, neopentyl glycoldicaprylate/dipelargonate/dicaprate, neopentyl glycol diethylhexanoate,neopentyl glycol diheptanoate, neopentyl glycol diisostearate, neopentylglycol dilaurate, ozokerite, palm alcohol, palm kernel alcohol,paraffin, pentaerythrityl tetramyristate, pentaerythrityl tetraoleate,pentaerythrityl tetrapelargonate, pentaerythrityl tetrastearate,pentaerythrityl trioleate, silica, synthetic beeswax, syntheticcandelilla wax, synthetic carnauba, vinyldimethyl/trimethylsiloxylicate,stearyl dimethicone crosspolymer VP/eicosene copolymer and VP/hexadecenecopolymer. Water soluble or water dispersable rheology modifiersinclude, but are not limited to, acetamide MEA, acrylamide/ethalkoniumchloride acrylate Copolymer, acrylamide/ethyltrimonium chlorideacrylate/ethalkonium chloride acrylate copolymer, acrylamides copolymer,acrylamide/sodium acrylate copolymer, acrylates/acetoacetoxyethylmethacrylate copolymer, acrylates/beheneth-25 methacrylate copolymer,acrylates/C₁₀₋₃₀ alkyl acrylate crosspolymer, acrylates/ceteth-20itaconate copolymer, acrylates/ceteth-20 methacrylate copolymer,acrylates/laureth-25 methacrylate copolymer, acrylates/palmeth-25acrylate copolymer, acrylates/palmeth-25 itaconate copolymer,acrylates/steareth-50 acrylate copolymer, acrylates/steareth-20itaconate copolymer, acrylates/steareth-20 methacrylate copolymer,acrylates/stearyl methacrylate copolymer, acrylates/vinyl isodecanoatecrosspolymer, acrylates/vinyl neodecanoate crosspolymer, acrylicacid/acrylonitrogens copolymer, agar, agarose, algin, alginic acid,ammonium acryloyldimethyltaurate/vinyl formamide copolymer, ammoniumacryloyldimethyltaurate/VP copolymer, ammonium alginate, ammoniumchloride, amylopectin, Avena sativa (oat) kernel flour, bentonite,calcium alginate, calcium carrageenan, C₂₀₋₄₀ alkyl stearate, carbomer,carboxybutyl chitosan, carboxymethyl hyroxyethylcellulose, carboxymethylhydroxypropyl guar, cassia Gum, cellulose gum, cetylhydroxyethylcellulose, C₁₂₋₁₄ hydroxyalkyl, hydroxyethyl sarcosine,cocamide DEA, cocamide MEA, decyl HDI/PEG-180 crosspolymer,decyltetradeceth-200 isostearate, dextrin, dimethicone/PEG-10crosspolymer, dimethicone/PEG-15 crosspolymer,dimethylacrylamide/ethyltrimonium chloride methacrylate copolymer,disteareth-75 IPDI, disteareth-100 IPDI, gelatin, gellan gum, hectorite,hydrated silica, hydrolyzed cellulose gum, hydroxybutyl methylcellulose,hydroxyethylcellulose, hydroxyethyl ethylcellulose, hydroxypropylchitosan, hydroxypropyl guar, hydroxypropyl methylcellulose,hydroxypropyl methylcellulose stearoxy ether, hydroxypropyl starch,hydroxypropyl starch phosphate, hydroxypropyl xanthan gum,isopolyglyceryl-3 dimethicone, isopolyglyceryl-3 dimethiconol, laurylhydroxysultaine, lauryl/myristyl glycol hydroxypropyl ether, laurylPEG-9 polydimethylsiloxyethyl dimethicone, lauryl polyglyceryl-3polydimethylsiloxyethyl dimethicone, levan, magnesium alginate,magnesium aluminum silicate, magnesium silicate, magnesium trisilicate,methoxy PEG-22/dodecyl glycol copolymer, methylcellulose, methylethylcellulose, methyl hydroxyethylcellulose, microcrystallinecellulose, montmorillonite, myristamidopropyl hydroxysultaine,oatamidopropyl betaine, octacosanyl glycol isostearate, octadecene/MAcopolymer, pectin, PEG-150/decyl alcohol/SMDI copolymer, PEG-175diisostearate, PEG-190 distearate, PEG-15 glyceryl tristearate, PEG-140glyceryl tristearate, PEG-240/HDI copolymer bis-decyltetradeceth-20ether, PEG-100/IPDI copolymer, PEG-180/laureth-50/TMMG copolymer,PEG-10/lauryl dimethicone crosspolymer, PEG-15/lauryl dimethiconecrosspolymer, PEG-2M, PEG-5M, PEG-7M, PEG-9M, PEG-14MPEG-20M, PEG-23M,PEG-25M, PEG-45M, PEG-65M, PEG-90M, PEG-115M, PEG-160M, PEG-180, PEG-120methyl glucose triisostearate, PEG-120 methyl glucose trioleate, PEG-150pentaerythrityl tetrastearate, PEG/PPG-120/10 trimethylolpropanetrioleate, PEG/PPG-120/10 trimethylpropane trioleatePEG-150/stearylalcohol/SMDI copolymer, polyacrylate-3, polyacrylate-10,polyacrylate-11, polyacrylic acid, polycyclopentadiene, polyester-5,polyether-1, polyethylene/isopropyl maleate/MA copolyol,polyglycerin-20, polyglycerin-40, polyglyceryl-3 disiloxane dimethiconepolyglyceryl-3 polydimethylsiloxyethyl dimethicone, polyquaternium-86,polyvinyl alcohol, potassium polyacrylate, potato starch modified, PVPmontmorillonite, sodium acrylates/acrylonitrogens copolymer, sodiumacrylates copolymer, sodium acrylates crosspolymer, sodiumacrylate/sodium acrylamidomethylpropane sultanate copolymer, sodiumacrylate/sodium acryloyldimethyl taurate/acrylamide copolymer, sodiumacrylates/vinyl isodecanoate crosspolymer, sodium acrylate/vinyl alcoholcopolymer, sodium acryloyldimethyl taurate/acrylamide/VP copolymer,sodium carboxymethyl beta-glucan, sodium carboxymethyl starch, sodiumcarrageenan, sodium cellulose sulfate, sodium chloride, sodiumhydroxypropyl starch phosphate, sodium isooctylene/MA copolymer, sodiumpolyacrylate, sodium silicoaluminate, sodium starch octenylsuccinate,sodium sulfate, steareth-100/PEG-136/HDI copolymer, tapioca starch,TEA-alginate, TEA-carbomer, trehalose hydroxypropyltrimonium chloride,tridecyl alcohol, undecyl alcohol, wheat germamidopropyl betaine,xanthan gum, yeast, polysaccharides, and Zea Mays (corn) starch.

Still other optional components that may be desirable for use in theskin-adhesive and absorbent gel composition include those cosmetic andpharmaceutical ingredients commonly used in the skin care industry.Examples include abrasives, absorbents, aesthetic components(fragrances, pigments, colorings/colorants), essential oils, skinsensates, astringents (e.g., clove oil, menthol, camphor, eucalyptusoil, eugenol, menthyl lactate, witch hazel distillate), anti-acneagents, anti-caking agents, antifoaming agents, antioxidants, binders,biological additives, buffering agents, bulking agents, chelatingagents, chemical additives, colorants, cosmetic astringents, cosmeticbiocides, denaturants, drug astringents, external analgesics, opacifyingagents, propellants, reducing agents, sequestrants, skin bleaching andlightening agents (e.g., hydroquinone, kojic acid, ascorbic acid,magnesium ascorbyl phosphate, ascorbyl glucosamine), skin-moisturizingagents, skin-conditioning agents, skin soothing and/or healing agents(e.g., panthenol and derivatives thereof, aloe vera, pantothenic acidand derivatives thereof, allantoin, bisabolol, dipotassiumglycyrrhizinate), hemorrhoid treating agents (e.g., witch hazel),prebiotics, probiotics, urinary tract infection treating agents, yeastinfection treating agents, bacterial vaginosis treating agents, skintreating agents, sunscreens, thickeners, and vitamins, and combinationsthereof. Examples of these and other agents are disclosed in The CTFACosmetic Ingredient Handbook, 12^(th) Ed. (2007), which is herebyincorporated by reference to the extent that it is consistent herewith.

The amounts of the optional components will depend on the type ofskin-adhesive and absorbent gel composition used and as well as thedesired benefits of the optional components. In one embodiment, the gelcomposition includes from about 0.001% (by total weight composition) toabout 60% (by total weight composition) skin benefit agent and, inanother embodiment, from about 0.01% (by total weight composition) toabout 30% (by total weight composition) skin benefit agent, and evenfrom about 0.01% (by total weight composition) to about 20% (by totalweight composition) skin benefit agent.

More than one skin benefit agent can be used depending on the desiredeffect(s) of the benefit agents.

The skin benefit agent may be homogeneously dispersed throughout theskin-adhesive and absorbent gel composition or may be located atdiscreet portions of the gel composition. For example, a skin benefitagent such as a humectant that functions as a skin moisturizer may belocated at the peripheral portions of the gel composition that are morelikely to contact the skin. Further, additives relating to vaginalecology such as prebiotics, probiotics, pH balance agents, urinary tractinfection treating agents, yeast infection treating agents and bacterialvaginosis treating agents and additives such as hemorrhoid treatingagents could be located at the central portions of the gel composition.Alternatively or additionally, the skin benefit agent may bemicro-embossed or printed on the surface of the gel composition. In someembodiments, the skin benefit agent is microencapsulated and dispersedthroughout the gel composition.

Packaging

The absorbent article 100 may be individually packaged to maintain thedesired moisture content of the gel composition. For example, theabsorbent article 100 may be packaged in a hermetically sealed foilenvelop similar to the packaging used for moist toilettes or “wet-naps.”Other packaging materials include polyester or aluminized polyester.

The following description includes non-limiting examples of specificembodiments of absorbent articles that further illustrate the presentdisclosure.

EXAMPLES Example 1

Two-Layered Absorbent Article

The absorbent article includes a substrate layer that may be a film,nonwoven, woven, netting or foam. A skin-adhesive and absorbent gelcomposition is attached to the body-facing surface of the substrate.

Example 2

Two-Layered Absorbent Article with a Contoured Fit

The absorbent article is constructed according to Example 1; however theskin-adhesive and absorbent gel composition is shaped and sized to matchthe contours of female genitalia. Particularly, the gel composition isgenerally dome shaped, i.e., it is thicker in its central portion andthinner in the peripheral portions.

Example 3

Two-Layered Absorbent Article with a Fibrous Web

The absorbent article includes a substrate as in Example 1. Askin-adhesive and absorbent gel composition is attached to thebody-facing surface of the substrate. The gel composition includes afibrous web with the threads of the web being coated by a hydrogel.

Example 4

Two-Layered Absorbent Article with Two Gel Layers

The substrate of the absorbent article is composed of afluid-impermeable gel such as fluid-impermeable silicone gel. A secondgel composition that is skin-adhesive and absorbent is attached to thebody-facing surface of the gel substrate. The substrate is thinner inthe z-direction than the gel composition.

Example 5

Three-Layered Absorbent Article

The absorbent article includes a substrate as in Example 1. On thebody-facing surface of the substrate is an absorbent core. The absorbentcore may be composed of a hydrogel composition. A perforated liner madeof a hydrophobic silicone gel is attached to the body-surface side ofthe absorbent core. The perforations of the liner may be in the form ofapertures, slots, funnels or holes.

Example 6

Three-Layered Absorbent Article that Includes Hydrating Perforated Liner

The absorbent article includes a substrate and absorbent core as inExample 5. The perforated liner of the absorbent article is a siliconegel that absorbs and draws away menstrual fluid but maintains hydrationof the skin that contacts the liner. The perforated liner is sized andshaped to contact the labial region of the wearer.

Example 7

Three-Layered Absorbent Article that Includes Skin Benefit Agents

The absorbent article of Example 5 includes skin benefit agents.Particularly, the central portion of the absorbent core includesprobiotics and pH balance agents for vaginal ecology and the peripheralportions of the absorbent core include a moisturizer to prevent skinirritation.

Example 8

Four-Layered Absorbent Article

The absorbent article includes a substrate layer as in Example 1attached to the body-facing surface of the substrate is an absorbentcore that contains an absorbent gel. Attached to the body-facing surfaceof the absorbent core is a fibrous web that is coated with a hydrogelthat provides dimensional resilience (in the x, y and z direction) toprevent collapse of the absorbent article and loss of fluid capacity. Aperforated liner made of a hydrophobic silicone gel is attached to thebody-facing surface of the fibrous web. The perforated liner iscomfortable to the wearer, i.e., in that it does not irritate the skin,and is malleable.

Having described the disclosure in detail, it will be apparent thatmodifications and variations are possible without departing from thescope of the disclosure defined in the appended claims.

In view of the above, it will be seen that the several objects of thedisclosure are achieved and other advantageous results attained.

As various changes could be made in the above formulations andsubstrates/articles without departing from the scope of the disclosure,it is intended that all matter contained in the above description shallbe interpreted as illustrative and not in a limiting sense.

What is claimed is:
 1. An absorbent article consisting of a fluidimpermeable substrate having a body-facing surface and a garment-facingsurface, a perforated liner composed of a silicone gel, and an absorbentcore interposed between the substrate and perforated liner, theabsorbent core comprising an absorbent gel composition, wherein theabsorbent gel composition comprises a hydrogel composed of monomersselected from the group consisting of N-vinyl pyrrolidone, hydroxyethylmethacrylate, methacrylic acid or its salt, styrene sulfonic acid or itssalt, potassium sulfopropyl acrylate, dimethyl acrylamide, dimethylamino ethyl methacrylate or its quaternary salt derivative, acrylamidomethyl propane sulfonic acid or its salt and mixtures thereof, whereinthe absorbent gel composition further comprises an adhesion modifierdispersed within the absorbent gel composition, wherein the adhesionmodifier is selected from allyl methacrylates crosspolymer, allylmethacrylate/glycol dimethacrylate crosspolymer, laurylmethacrylate/glycol dimethacrylate crosspolymer and derivatives thereof,wherein the hydrogel is intertwined with a fibrous web, and wherein theratio of the hydrogel to the fibrous web is from about 30:1 to about100:1 by basis weight.
 2. An absorbent article as set forth in claim 1wherein the absorbent gel composition is capable of absorbing at leastabout 20% of its weight in water.
 3. An absorbent article as set forthin claim 1 wherein the absorbent get composition is capable of absorbingat least about 100% of its weight in water.
 4. An absorbent article asset forth in claim 1 wherein the absorbent gel composition is capable ofabsorbing at least about 1000% of its weight in water.
 5. An absorbentarticle as set forth in claim 1 wherein the absorbent gel compositioncomprises an aerogel.
 6. An absorbent article as set forth in claim 1wherein the hydrogel is formed from a composition comprising a monomer,initiator, cross-linking agent and an solvent.
 7. An absorbent articleas set forth in claim 1 wherein the absorbent gel composition has athree-dimensional cross-linked structure.
 8. An absorbent article as setforth in claim 1 wherein the perforated liner is hydrophobic.
 9. Anabsorbent article as set forth in claim 1 wherein the absorbent gelcomposition comprises a skin benefit agent, wherein the skin benefitagent is selected from the group consisting of antiperspirants,deodorants, skin moisturizers, humectants, pH modulators, soothingagents, antimicrobials, preservatives, film formers, and combinationsthereof.
 10. An absorbent article as set forth in claim 1 wherein theperforated liner includes a skin benefit agent, wherein the skin benefitagent is selected from the group consisting of antiperspirants,deodorants, skin moisturizers, humectants, pH modulators, soothingagents, antimicrobials, preservatives, film formers, and combinationsthereof.
 11. An absorbent article as set forth in claim 1 wherein theperforated liner is characterized by a peel strength of perforated linerto the body-facing surface of greater than about 800 grams per inch. 12.An absorbent article as set forth in claim 1 wherein the substrate iscomposed of a material selected from the group consisting of a polymericfilm, polymeric foam, woven fabric, nonwoven fabric and knitted fabric.13. An absorbent article as set forth in claim 1 wherein the perforatedliner is sized and shaped to cover the vulva region of a wearer.
 14. Anabsorbent article as set forth in claim 1, wherein the perforated lineris characterized by a peel strength of perforated liner to the wearer ofless than about 20 grams per inch.